MHIRJ Aero Advisory Services - Sustainable Aviation Road Map

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Disclaimer: This report is provided by MHI RJ Aviation ULC (“MHIRJ”) for information purposes only and does not constitute an offer to do business or a promise or commitment of any kind. MHIRJ makes no representations, warranties or conditions, expressed or implied, statutory or otherwise regarding any matter, including any warranties, or conditions of merchantability, quality, non-infringement, or fitness for a particular purpose or that the information will be error-free, accurate, or complete. This report and the information contained herein are proprietary and may not be copied, reproduced in whole or in part, or distributed to anyone other than the intended recipient. MHIRJ aims to use reliable sources when writing our reports and it should not be relied on as such. Clients should not base business decisions on the information provided but should seek professional advice. MHIRJ disclaims any and all liability relating to or arising out of the use of the information contained in this report to the fullest extent permissible by law.


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EXECUTIVE SUMMARY . . . . . . . . . . . . . . . . . . . 3

2. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . 6

5. AIRCRAFT SEGMENTS . . . . . . . . . . . . . . . . . . 24 5.1. Commuter Segment . . . . . . . . . . . . . . . . . . . . . . . . . . 24 5.2. Regional Segment . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 5.3. Narrowbody Segment . . . . . . . . . . . . . . . . . . . . . . . . 27


GREENHOUSE GAS EMISSIONS IN AVIATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

3.1. Continuous Improvement . . . . . . . . . . . . . . . . . . . . . . . . 8 3.2. Sustainable Aviation Fuel . . . . . . . . . . . . . . . . . . . . . 11 3.3. Hydrogen Combustion . . . . . . . . . . . . . . . . . . . . . . . . 13 3.4. Hydrogen Fuel Cell . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 3.5. Battery Electric . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 3.6. A note about Hybrid Solutions . . . . . . . . . . . . . . . . . 17

5.4. Widebody Segment . . . . . . . . . . . . . . . . . . . . . . . . . . 28 5.5. A Note on Advanced Air Mobility . . . . . . . . . . . . . . . 29

6. IMPACT ON STAKEHOLDERS . . . . . . . . . . . . 30 6.1. Airlines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30 6.2. Airports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 6.3. Aircraft Manufacturers and Suppliers . . . . . . . . . . 32 6.4. Governments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 6.5. Regulators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 6.6. Other Stakeholders . . . . . . . . . . . . . . . . . . . . . . . . . . 34


FOR COMMERCIAL AVIATION . . . . . . . . . . . . 18

4.1. Commercial Aircraft Market . . . . . . . . . . . . . . . . . . . 18 4.2. Range Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 19

7. CONCLUSION . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 8. HOW WE CAN HELP . . . . . . . . . . . . . . . . . . . . . 35

4.3. E volution of Energy Demand for Commercial Aviation 2021-2050 . . . . . . . . . . . . . . .


4.4. Sustainable Aviation Timeline . . . . . . . . . . . . . . . . . 21 4.5. A Note about Carbon Offsets . . . . . . . . . . . . . . . . . . 23

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9. APPENDIX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37



Vice President, Market Insights

A lot is currently being said and discussed around emerging technologies that would contribute to reducing the carbon footprint of commercial aviation in the coming years. Announcements of new projects with ambitious timelines can create confusion as to what can be realistically achieved and when. With our extensive aircraft OEM background and deep understanding of the commercial aviation market, we, at MHIRJ Aero Advisory Services, have decided to provide a balanced and unbiased view on the development and timing of emerging technologies and their role in achieving the goal to Net Zero aviation. To achieve this, we have created a model that can forecast aircraft-based energy requirements – kerosene, SAF, hydrogen, electricity – over the next 30 years. And this is for a specific aircraft segment, a specific airport, an entire country, or the whole industry. This Sustainable Aviation Roadmap assesses the main approaches to addressing commercial aviation sustainability, their implementation in each aircraft segment, and the related timelines for adoption. A forecast for the roll-out is provided as well as the impact on the various industry stakeholders. Finally, a recommendation is provided on where the industry should focus its efforts to achieve its sustainability targets. This document is only a top-level, synthetic view of where, how, and when we see the Sustainability revolution unfold in commercial aviation. There is much more under the surface and, should you want more, don’t hesitate to contact us. Happy, green reading!

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• This Sustainable Aviation Roadmap looks at the challenges of achieving the target of Net Zero carbon in commercial aviation by 2050, specifically the roll-out of new technologies and how they will impact the composition of the commercial aircraft fleet as well as key industry stakeholders. We provide an analysis of market trends, fleet evolution, sustainability developments, technology maturity, product strategies, and airline requirements. • Achieving rapid industrialization of SAF production is the most effective way to reduce the carbon impact of commercial aviation. Policies that accelerate its production, incentivize its use, and reduce its cost should be prioritized. • Continuous improvement efforts will achieve the greatest impact in the short term. Many efficiency improvements can be implemented without massive investments in technology. Accelerating the implementation of operational and navigation enhancements such as those planned in the FAA NextGen and EASA SESAR programs will reduce greenhouse gas emissions immediately. • New technologies will be introduced into smaller aircraft segments first then migrate into the larger segments as the technologies mature. We will see the first electric and hydrogen fuel cell commuter aircraft enter into service this decade, with hydrogen combustion-powered narrowbodies around 2040. • Narrowbody and widebody aircraft produce over 95% of the industry’s greenhouse gas emissions, therefore, while the introduction of new technologies on smaller aircraft will be important for the development of sustainable solutions, they will have minimal impact on the overall carbon footprint until they make their way onto larger platforms. • Carbon-free fuels (electric, hydrogen) will require significant infrastructure investments to develop the novel transportation network and the re-fueling procedures that will be required to support their use. • The timing for the introduction of new technology programs will be influenced by the lifecycle of existing aircraft programs which typically last 20-25 years. The enormous investment required to validate and certify a new program dictates a cautious approach to novelty. • Regional aviation provides a vital service to smaller communities ensuring connectivity and supporting the economy. A rapid roll-out of clean, quiet technologies in the smaller aircraft segments will be crucial to supporting growth in these markets. • Acting now to improve efficiency today is vital. Post-Covid, the aviation industry will return to growth propelled by increased GDP and propensity to travel, the same forces that we saw in the past. While investing now in new technologies that will deliver zero-carbon solutions later, no time should be wasted to renew fleets and adopt green measures. • Many stakeholders will have an impact on the rate of acceptance of the various sustainability solutions available to commercial aviation. It will be crucial to have a coordinated and synchronized effort by all of those involved including airlines, airports, manufacturers, governments, certification authorities, and fuel suppliers, among others.

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AIRCRAFT KEROSENEEQUIVALENT DEMAND 2020-2050 Commercial Aviation Energy Requirement


Fuel Demand for Industry Growth

2-3% CAGR


Continuous Improvement


-1.5% per year

Sustainable Fuels


Hydrogen Combustion Hydrogen Fuel Cell Electricity SAF

300 200 100 0

Carbon Offsets 2020










Hy drogen F uel Cell

Hy drogen Combustion

Total Fuel Demand

Efficiency Improvement

MAAS Sustainability Forecast

PRIVATE AND CONFIDENTIAL © MHI RJ Aviation ULC or its affiliates. All rights reserved.

Mton equivalent

Net Zero Objective

FIGURE 2- COMMERCIAL AIRCRAFT FLEET FORECAST B Figure 1 – Commercial Aircraft Kerosene-equivalent Demand 2020-2050 FUEL TYPE 3

Fleet Forecast by Fuel Type 100%








H2 Fue

0% 2020-2030






H2 Combu

Kero 100%







0% 2020-2030




H2 Fuel Cell


H2 Combustion





Figure 2 – Commercial Aircraft Fleet Forecast by Fuel Type


To achieve the target of Net Zero Carbon by 2050, aviation will need to overcome many challenges. Solid knowledge of aircraft development, industry trends and practices, and government policies will be critical to overcoming the hurdles and achieving success. For those who do, the future is full of potential. With its aircraft manufacturer DNA and its deep knowledge of the airline industry, MHIRJ Aero Advisory Services provides comprehensive market strategy solutions, helping airlines, airports, vendors, and many other actors to maximize profitability, re-think their business and anticipate the future.

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Figure 3- Source of man-made CO2 emissions. (Sourc INTRODUCTION ATAG Fact Sheet #2, Aviation and climate change2)

The contribution of aviation to society, human development, prosperity, and growth is unquestionable. It is ultimately a crucial service bringing people together. Whether it is supporting business and trade, visiting friends and family, or vacationing and discovering new cultures, there has been a steady increase in the propensity to travel over the years. • Aviation has also been a lightning rod for environmental activism, being the target of campaigns such as flygskam. Today aviation contributes to approximately 2.5% of manmade carbon emissions and ICAO has been proactive in setting targets for reducing the environmental impact of aviation. In fact, since 1990, the amount of CO2 per passenger kilometer has decreased by more than 50%. However, climate change is an existential threat to humanity, and to limit global warming to no more than 1.5oC, everyone, including aviation, will need to do their par t to reduce the production of Greenhouse Gases. At its Annual General Assembly in October 2021, IATA set an ambitious target for airlines of Net Zero Carbon emissions by 20501.

Cement 3%

Chemicals 2%

Waste 3%

Deforestation and Crop Burning 6%

Agriculture 13%

Aviation 2% Shipping 2%

Industry 40%

Road transport 12%

Buidings 18%

Figure 3 – Source of man-made CO2 emissions. (Source: ATAG Fact Sheet #2, Aviation and climate change2)

ANALYSIS AND METHODOLOGY Aviation is a challenging business, where technical, regulatory, financial aspects – just to name a few – must be evaluated for any development or change implementation. The demanding regulatory environment in which aviation operates ensures that a remarkable safety record is maintained. This makes aviation a difficult-to-abate business. To assess the various options available to address sustainability, we look at three key areas: • Feasibility: How mature is the technology. We look at the technology readiness, for example: what stage of development has the technology reached? Is it just a concept or has it been used in a demonstrator (scale or full-size)? Is it an adaptation of existing aircraft technology, used in a different category of aircraft? sIs the technology used in other industries? How difficult will it be to adapt to aviation? What are the hurdles to certification and what other systems does it impact? • Applicability: How easy it is to provide the technology to the aviation industry. Here we consider the required investment into the supply chain and infrastructure that is necessary to meet the volume needs of the aviation industry. What is the production capacity? Is there sufficient industrialization? What is global distribution? Does a transportation network exist? Can a local supply source be developed?

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• Suitability: Does the technology meet the requirements for aviation? Aviation has extremely demanding performance requirements that make many technologies used in other industries not suitable or not economical for aviation. We look at the investment and compromises required to adapt to the constraints and limitations imposed by the unique demands of the airborne environment. In addition, we integrate aircraft program lifecycles and fleet replacement requirements from our global market forecast. Our proprietary model takes into consideration the above considerations while generating fleet requirement scenarios for each segment and each technology. This paper represents the outcome of our sustainability model. It outlines some of the challenges facing commercial aviation and provides our view of a realistic roadmap to achieving sustainability.



There are several different approaches currently available to reduce the impact of greenhouse gas production. They vary from simple operational changes that can be implemented today but have a small impact, to complete re-designs of aircraft and their related infrastructure that will have a large impact on emissions but will take many years4for the technology to mature and be implemented. Achieving sustainability will necessarily involve Figure Strategies to reduce Greenhouse Gas Emissions in a combination of these technologies.


Small Continuous Improvement

Net Zero Sustainable Aviation Fuels

Zero Carbon Hydrogen Combustion

True Zero Hydrogen Fuel Cell

Large Battery


GHG Impact

-1.5% / year




Figure 4 – Strategies to reduce Greenhouse Gas Emissions in Aviation


ATM: Air Traffic Management, GHG: Greenhouse Gas Source: World Economic Forum: Clean Skies for Tomorrow, SAF as a Pathway for Net-Zero Aviation, 2020

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PRIVATE AND CONFIDENTIAL © MHI RJ Aviation ULC or its affiliates. All rights reserved.

Change in Emission Levels


Figure 5- Operational efficiency since 1990 (Source: ATAG Fact Sheet #3, Tracking aviation effic



250 200


150 100 50















0 1990

Over the last 20 years, commercial aviation has improved efficiency by more than 2% per year on average, which translates directly into lower carbon emissions. This adds up to a tremendous impact: for example, a 1% reduction in the amount of CO2 generated by commercial aviation in 2019 is equivalent to roughly 40 times the carbon offset from SAF in 2021. There are many improvements available today that require a minimum amount of investment and will generate immediate savings.

Grams of CO2 per passenger km


Figure 5 – Operational efficiency since 1990 (Source: ATAG Fact Sheet #3, Tracking aviation efficienc3)


Figure 6 – CFM RISE engine

Each generation of aircraft design represents a stepwise improvement inefficiency. The introduction of the A320neo and the 737 MAX each promised fuel savings of approximately 20% compared to the models that they replaced. Similar savings were achieved for the C Series/A220, Embraer E2, 787 and A350 models. In other words, simply replacing an older generation model with a new, more efficient model, will yield important savings. Looking forward, the next generation of aircraft engines will deliver comparable efficiency gains with CFM claiming that their RISE narrowbody engine will be 20% more efficient than the current LEAP model4 and Rolls Royce claiming a similar improvement for their widebody UltraFan engine compared with the current generation. More revolutionary solutions include distributed propulsion and hybrid configurations.

Aerodynamics for each generation of aircraft continue to improve as well, with new winglet designs (Airbus Sharklets, Boeing Split Scimitar) or higher aspect ratio wings such as the Embraer E2 or the Boeing 777X with its folding wingtips. Future developments include greater use of laminar flow surfaces, morphing wing surfaces, or more extreme arrangements such as truss-braced wings and blended wing body configurations which could also lead to innovative cabin configurations.

Figure 7 – Boeing/NASA SUGAR volt

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Aircraft systems also contribute to improved efficiency such as the use of a more electric architecture on the Boeing 787 Dreamliner or the full fly-by-wire on the Embraer E2 models, electric actuators on the Airbus A380 and electric brakes on the A220 which reduce the use of hydraulics. Weight reductions through increased use of composites and innovative manufacturing techniques, such as additive manufacturing, have a direct impact on fuel burn as well. Historical aircraft family replacement cycles last about 20-25 years. Depending on the complexity of the redesign, the maturity of the technologies that are being incorporated and the experience of the aircraft manufacturer, another 10 to 15 years may be needed to account for new technology development prior to aircraft certification.

Figure 8- Historical aircraft family replacement cycles Aircraft







TurboProp Dash8-1/2/300 Dash8-400 ATR Family Regional Jet ERJ Ejet E1 Family Ejet E2 Family CRJ200 CRJ7/9/1000 Narrowbody 737-200 737 Classic 737 NG 737 Max A320ceo Family A320neo Family Widebody 767 Family 787 Family A300/A310 A330 Family A330neo Family 777 Family 777X Family A340 Family A350 Family Launch to Certification


EIS to End of Production

Figure 8 – Historical aircraft family replacement cycles

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OPERATIONAL EFFICIENCY How an aircraft is operated can have a major impact on its efficiency. Services such as SkyBreathe© from OpenAirlines use big data to monitor a myriad of variables to identify the most efficient solution and provide a feedback loop allowing pilots and airlines to continuously assess and improve their performance. These improvements do not require any investment by the airlines into additional technology and deliver cost savings in addition to the sustainability benefits.


Energy-efficient method of descending: Continuous descent with reduced engine propulsion

Regular method of descending: Engine

Active runway

thrust increased in level cruising flight

Figure 9 – Example of Continuous Descent Operations (Source: Eurocontrol5)

Over the last decade, the FAA with NextGen and EASA with SESAR have invested billions of dollars to upgrade the US and European airspace and improve efficiency. Cooperation between the various stakeholders (airports, Air Traffic Control (ATC), Air Navigation Service Providers (ANSPs) and airlines) is required to achieve the most efficient routing, eliminate holding and reduce taxi times. In addition, to improve sustainability, more efficient use of the airspace will result in other benefits including fewer delays and greater on-time arrival performance which will benefit passengers as well.

nautical miles/day

tonnes of fuel/day

fewer CO2 tonnes/day

in fuel costs savings/day

Figure 10 – Estimated Savings from Free Route Airspace in Europe (Source: Eurocontrol6)

Clearly there are many low-hanging fruits available today that can improve sustainability immediately, starting by operating latest-generation aircraft. These are the type of improvements that have generated year-over-year efficiency gains in the past. Continuous improvements in aircraft or engine design provide the opportunity to easily and relatively cheaply introduce greener solutions. Acceleration of the adoption of operational savings offered by FAA NextGen and EASA SESAR programs will reduce the greenhouse gas emissions from all aircraft segments while also reducing costs. Another consideration that is often overlooked is the compounding benefit of time, whereby implementing the savings sooner multiplies their impact over the longer term.



However, continuous improvement alone will not be enough to achieve our target of Net Zero carbon by 2050 and we will need to look for additional solutions to close the gap.

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3.2. SUSTAINABLE AVIATION FUEL Today almost all flights are powered by kerosene (also known as Jet-A), a petroleum product made from refining crude oil which, when burned, produces CO2, NOx, soot and other pollutants that impact the environment. An alternative to kerosene is Sustainable Aviation Fuel (SAF) which is currently certified for use in blends of up to 50% with kerosene. The production of SAF takes CO2 out of the atmosphere, resulting in a 50%-80% net reduction of aircraft CO2 emissions. SAF also burns cleaner than kerosene since it does not contain sulphur and other pollutants. Because SAF is a drop-in replacement for kerosene, no modifications are required for the aircraft, and it can be used with existing airport refueling infrastructure. The 2021 global production target for SAF was 100 million liters7 from a few specialized suppliers. There are 2 main categories of SAF: Biofuel and Synthetic Fuel (also known as electrofuels).

BIOFUEL Biofuel uses a sustainable biomass feedstock that is modified into SAF through a chemical process. Beyond its lower CO2 footprint, biofuel allows for it to be sourced locally providing extra revenue for farmers and communities, increasing biodiversity, reducing methane generation and watershed pollution, and is potentially less susceptible to market swings and dependence on OPEC. However, there is limited availability of suitable biomass as well as competition from other applications such as BioDiesel. Today the cost of biofuel is about 2-3 times that of kerosene.

How is sustainable aviation fuel made? U s e d cooking oil

4 Fuel is delivered to airport and into wing.

From waste to wingtip – the production journey for sustainable aviation fuel (SAF)

Forestry waste

Household waste

1 Feedstock is collected – such as household waste or waste oils.

Using SAF can reduce lifecycle carbon emissions by up to 80% compared to the traditional fuel it replaces.

3 Traditional jet fuel blended with

sustainable aviation fuel to make it suitable for use in aircraft.

2 Feedstock is conver ted to

Fuelling a sustainable future Figure 11 – Sample BioFuel Pathway (Source BP)

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sustainable aviation fuel.


SYNTHETIC FUEL / ELECTROFUELS SynFuel is produced with sustainable hydrogen created using renewable electricity and carbon capture to form SAF through a synthesis process. Today, this process is only at the demonstration level resulting in a production cost that is about 5 times higher than kerosene.

Figure 12 – Sample SynFuel Pathway (Source: SAF+ Consortium)

Rapid adoption of sustainable aviation fuels is the quickest and most effective way to decarbonize aviation. There is a pull from the market with many airlines committing to using 10% SAF by 2030. There is support from governments with Refuel EU in Europe and the White House’s SAF Grand Challenge in the United States. There is interest among fuel providers in the construction of biofuel refineries. However, the industrialization of biofuel needs to accelerate. Today’s production represents less than 0.1% of the industry demand for kerosene and IATA is forecasting a ramp-up to 5% by 2030. Airlines such as Air Canada and Lufthansa are encouraging passengers to offset their personal carbon footprints by purchasing SAF and corporations such as Microsoft are offsetting their business travel with SAF. All major aircraft manufacturers have either operated or planned demonstration flights fueled by 100% SAF and the major engine OEMs are planning to certify new engines with 100% SAF. These actions will have a measurable impact on the sustainability of commercial aviation however, the industry needs more SAF more rapidly to be able to fuel the planes.



While the amount of biomass required to make biofuel will become limiting, synfuel offers the potential for unlimited supply. In addition, the use of carbon capture in the manufacture of synfuel actively removes CO2 from the environment, resulting in a net-zero CO2 life cycle. Accelerating the development of synfuel must be a top priority to meet the market demand. Until sufficient SAF is available, programs such as book-and-claim can be used to maximize sustainability impacts. Book-and-claim will allow more SAF usage throughout the entire system by enabling aircraft operators who choose to use the renewable fuel to purchase it even where it is not physically present, with the actual fuel being dispensed to a different aircraft at another location, typically close to a SAF production center. The volume of SAF in the transaction is tracked and verified and the carbon credits are assigned to the purchaser of the fuel rather than to the aircraft that receives it. This process ensures proper accounting of the environmental benefits and avoids unnecessary fuel transportation that would reduce the lifecycle greenhouse gas savings.

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Figure 13- Global hydrog SUSTAINABLE AVIATION ROADMAP Position Paper

3.3. HYDROGEN COMBUSTION Hydrogen offers many desirable attributes over carbon-based fuels, most importantly it does not generate CO2 when burned. As a result, a greater reliance on hydrogen is one of the key elements of the overall decarbonization strategy, especially for high-energy industries such as steel production. Hydrogen can be produced by several different methods which are categorized by color based on their sustainability impact. Green Hydrogen is produced on a CO2-neutral basis through the electrolysis of water using electricity generated from renewable energy sources such as wind energy, hydropower or solar energy.

Figure 13 – Global hydrogen production (source: IEA8)

IMPACTS ON AIRCRAFT DESIGN For hydrogen combustion, the conventional turbofan or turboprop engine is modified to burn hydrogen gas instead of kerosene fuel. This approach maintains the conventional engine design with systems adapted for the unique properties of hydrogen. The biggest challenge involves the onboard storage of hydrogen. Unlike kerosene, which is a liquid and can be stored in the wings of the aircraft, hydrogen is a gas and must be stored in tanks under pressure. In order to minimize the volume, cryogenic liquid hydrogen is used, which is cooled 9 to 21K (-253ºC or -421ºF). Even at this low temperature, hydrogen has a volumetric efficiency ¼ that of kerosene, which means that it requires 4 times the volume of hydrogen for an equivalent amount of energy. These super-cooled storage tanks are located in the fuselage and take up space that would otherwise be allocated to passengers or cargo. Hydrogen has a much higher gravimetric density than kerosene whereby 1 kg of hydrogen has the same amount of energy as 2.9 kg of kerosene. Ideally the lighter weight of the hydrogen will offset the increased structure required for its storage. While hydrogen combustion does not generate any CO2, it does produce NOx and water vapor which results in contrails. At this stage, the long-term outcome of hydrogen combustion is less clear. While the potential is definitely massive, being the only zero-carbon fuel source that is likely to deliver the performance required for jet-powered aircraft for the foreseeable future, it will also require massive investments to bring it to market and overcome the challenges of hydrogen storage. SynFuels offer many of the same benefits with less technical challenge. Early indications are that Biofuels burn cleaner than kerosene while the non-carbon emissions from hydrogen combustion are not well known at this time. At the end of the day this may be analogous to the battle between Betamax and VHS, where the eventual winner can only be determined with hindsight.



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3.4. HYDROGEN FUEL CELL Similar to hydrogen combustion, hydrogen fuel cells use hydrogen as a fuel source. The big difference is that instead of burning hydrogen, fuel cells use a chemical reaction to generate electricity, like a battery. Fuel cells are clean, quiet and produce water vapour as the only exhaust. Hydrogen fuel cells have been available for many years and are used for warehouse logistics, standby power and trucking. Newer technology is increasing the power density and reliability of these systems, making them more suitable for aviation applications.


Figure 14 – PEM Hydrogen Fuel Cell Diagram (source: Airbus9)

In addition to the hydrogen storage issues described in the hydrogen combustion section, a fuel cell-powered aircraft requires an entirely new electric powertrain and electric systems. The new design also brings new opportunities such as distributed propulsion, higher redundancy and more efficient systems. The weight and volume of the fuel cell, including its cooling system, limits the application to smaller aircraft today; however, developments that increase power output and reduce the amount of cooling required will lead to more compact systems in the future. The clean and quiet nature of hydrogen fuel cell aircraft should make them popular with passengers and neighbors alike. With water vapour as the only emission, they provide excellent sustainability credentials.

IMPACTS ON INFRASTRUCTURE In order to accommodate hydrogen-fueled aircraft (whether it is for hydrogen combustion or hydrogen fuel cell technology), the entire fuel supply chain must be developed for aviation. Airports will need to invest in new infrastructure to store, liquify and deliver the hydrogen to the aircraft. This will involve the development of new safety procedures on account of the cryogenic temperatures and will take longer to refuel the aircraft due to the higher volume required. It is anticipated that by the time the technology matures sufficiently for aircraft use, the hydrogen economy will have grown so that sources of green hydrogen will be more plentiful, and a transportation network will be in place. Today, the production cost of green hydrogen is about 5 times that of kerosene and the higher volume required increases the transportation cost. Sources of renewable electricity are expected to grow four-fold by 2030, which means that local production of hydrogen could be feasible, even on-site at the airports, which will dramatically reduce its cost.

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Today the development of hydrogen fuel-cell propulsion looks very promising with several start-ups bringing conversion kits to market in the next few years. To date, the adoption of fuel-cell technology has been frustratingly slow in other industries; however, many promising developments provide a reason to be optimistic that the technical hurdles can be overcome in the not-too-distant future. The electric powertrains of fuel-cell aircraft offer many of the same clean and quiet benefits of battery-electric systems with the bonus of a longer range, explaining the enthusiasm for this technology.



The biggest electric motors being developed today are in the 1MW-2MW range which is suitable for turboprop applications. It is possible that we will see a resurgence of turboprop aircraft in the next decade as new clean hydrogen fuel cell-powered models replace the ageing in-service fleet. Much will depend on the development of the hydrogen economy with the price and availability of green hydrogen needing to reach a certain threshold before this segment can really take off.

3.5. BATTERY ELECTRIC We can see a dramatic shift taking place in the automotive industry with the accelerating move to battery-electric vehicles. Most major automobile manufacturers have embraced future electric models and legislation is being enacted which will soon limit access to downtown areas to electric vehicles only. In the aviation world, there has been a wave of new Advanced Air Mobility (AAM) projects announced, most of which use battery-electric propulsion. This massive investment is sure to accelerate the development of battery technology.

Figure 15- Evolution of Battery energy and technology (source MHIRJ Aero Advisory Services) Evolution of Battery Energy Density

Wh/Kg 800

Suitable for Aviation




Li-Metal (Solid State)

PRIVATE AND CONFIDENTIAL © MHI RJ Aviation ULC or its affiliates. All rights reserved.


Li-Air Li-Sulfur

Li-Ion Battery (Energy Optimized) Li-Ion Battery (Current EV) 2020-2030



Figure 15 – Evolution of Battery energy and technology (source MHIRJ Aero Advisory Services)


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IMPACTS ON AIRCRAFT DESIGN Batteries provide greater flexibility in aircraft design; they can be located almost anywhere. Additionally, the weight does not decrease during the flight as the energy is consumed, which means that there is no impact on the aircraft center of gravity either. The batteries can be located close to the electric motors to reduce the amount of wiring required and distributed propulsion systems can improve efficiency and add redundancy. Electric motors and systems tend to be very reliable and require less maintenance than combustion-based alternatives. We are seeing the development of simplified vehicle operating systems in the AAM market that take advantage of these properties. An electric propulsor also weighs less than the turbine equivalent. Weight is a major factor limiting the penetration of battery technology in aviation. With a system energy density of about 1/15 that of kerosene, battery-powered aircraft end up weighing significantly more than kerosene-powered models, which limits the payload and range capabilities. Since batteries do not become lighter as the energy is consumed, there is an increasing penalty on landing performance vis-a-vis kerosene-powered aircraft as the energy requirement increases.

IMPACTS ON INFRASTRUCTURE In order to re-charge a battery-electric aircraft, an airport will need to have fast-charging stations available. Similar to the high-energy DC charging stations for automotive use, these could bring an aircraft back to full charge in about 30 minutes and could be located either at the gates or remotely. In order to be a sustainable solution, the electricity used must be from a renewable source. On-site solar panels could supplement the electricity required. When using renewable electricity, the battery-electric aircraft delivers zero greenhouse gas emissions. It is anticipated that large investments into battery technology should yield a stepwise improvement in energy density in the coming years that could double the available range for this technology.



We are likely to see the first commercial flights on battery-electric-powered aircraft take place before the end of the current decade. There is a tremendous amount of investment in the development of battery technology as well as the high-voltage systems and powertrains required for short flights. AAMs will likely lead this effort however commuter aircraft will not be far behind.

The maintenance cost advantages of an electric powertrain could be an important market accelerant if a viable battery recycling strategy can be developed as these will need to be replaced yearly due to degradation in order to restore energy capacity. Airports are already electrifying ground service equipment to reduce their carbon impact and therefore the charging infrastructure should be relatively straightforward to adapt to aircraft as well. Of course, the source of the electricity needs to be sustainable, requiring the installation of sufficient solar, wind or hydro-electric generation.

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There will be a huge demand for energy storage systems from other industries as well, with a corresponding demand for the scarce materials, such as cobalt, used in the production of batteries today. New designs that reduce the need for these materials and increase battery performance will be a top priority to lessen the environmental impact and improve the economics. Battery-electric propulsion offers the best sustainability credentials, stepwise changes in energy density will be required to expand its use beyond the shortest of missions and have a more meaningful impact on the overall aviation greenhouse gas emissions.

3.6. A NOTE ABOUT HYBRID SOLUTIONS Many different hybrid-powered aircraft solutions have been proposed. The inclusion of an electric motor, either in parallel or in series, with a conventional turbine engine enables the output of the turbine to be optimized for cruise thrust while the electric motor provides a supplemental boost for take-off and go-around situations. In this arrangement, the turbine engine can be made more efficient since it does not need to be oversized in order to endure high-load conditions. However, there is a weight penalty for carrying the batteries and electric motors that are only used for a short period of time. This falls into the category of continuous improvement as it is an evolution of current engine designs. Another hybrid architecture uses a gas turbine to drive an electric generator and the electricity is used to power electric propulsors. This is effectively an intermediate step on a pathway to full electric aircraft which takes advantage of the electric architecture but avoids the weight and volume challenges of battery and fuel cell designs. This approach provides sustainability benefits today through the use of more efficient architecture, such as the distributed propulsion system, while offering a pathway to zero-carbon flight in the future when Figure 16- Examples ofeither electric architecture the gas turbine could be replaced with batteries orpropulsion a fuel cell as those technologies mature.

Serial Hybrid: The propulsive power is electric and energy storage is active. Batteries can be relied upon to power the aircraft at certain times during flight

Parallel Hybrid: The propulsive power is electric and energy storage is active. Batteries can be relied upon to power the aircraft at certain times during flight All Electric: The propulsive power is all-electric. Electricity comes from batteries or other storage system eg. Hydrogen fuel cell Figure 16 – Examples of electric propulsion architecture

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Turbo-Electric: The propulsive power is electric. A gas turbine is used to generate electricity and there is no energy storage




Timelines and Scenarios

OEM Program Developments and Product Strategies Incumbents and new entrants

Aviation Market Growth Regional factors, route optimization, fleet profile

Socio-Economic Forecast Population growth, GDP growth, propensity to travel

Sustainable Aviation Forecast

Aviation Market Profile Today’s fleet, worldwide distribution, age profile Airline Requirements Business, Operational


Continuous Improvement Assessment Aircraft replacement cycle, technical and operational improvements

New Technology Evaluation Readiness level, performance capability

Market Requirements, Environmental policies, infrastructure

Figure 17 – Sustainable Aviation Forecast Inputs

4.1. COMMERCIAL AIRCRAFT MARKET The air transport industry is a key driver of the global economy, providing connectivity, supporting 87.7 million jobs and transporting 4.5 billion passengers in 2019. Commercial aviation generated about 915Mt of CO210 in 2019, which accounts for approximately 80% of the total aviation emissions, with 18% for cargo and 2% for business aviation. Emissions are correlated with Available Seat Kilometers (ASK), the passenger-carrying capacity of an aircraft. So, we see that while commuter and regional aircraft account for approximately 30% of the fleet in use, they represent only 4% of the greenhouse gas emissions. It means that the biggest impact on sustainability will come from addressing emissions of the narrowbody and widebody segments.

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The MHIRJ sustainable aviation forecast uses a proprietary model to determine how different sustainability pathways are likely to impact the commercial aviation market in order to achieve the IATA target of Net Zero by 20501. The first step is to assess the market demand for aviation over the time horizon, based on GDP growth and propensity to travel across the various regional markets. By reviewing the historical travel patterns and projecting the regional demographic trends, a fleet profile and model mix evolution is determined which provides a baseline fuel requirement and reference point from which various sustainability scenarios are analyzed. The forecast uses publicly available information as well as expert knowledge to assess multiple factors such as the technology readiness level, the certification challenge, the market size, product life cycles, the performance impact and potential benefits. The sustainable aviation forecast represents the reference scenario with 2-3% Figure 17- Sustainable Aviation Forecast Inputs industry growth, 1.5% annual efficiency improvement and nominal assumptions for each technology.


Figure 18- Market Share vs Carbon Share Global Commercial GHG contribution

Commuter (<20pax) 16%

Widebody (>240pax) 14%

Widebody (>240pax) 38%

Commuter (<20pax) 1%

Regional (21-100pax) 14% Narrowbody (101-240pax) 56%

Regional (21-100pax) 3%

Narrowbody (101-240pax) 58%

PRIVATE AND CONFIDENTIAL © MHI RJ Aviation ULC or its affiliates. All rights reserved.

Global Commercial Aircraft Fleet

* GHG: greenhouse gases

Figure 18 – Market Share vs Carbon Share 13

4.2. RANGE REQUIREMENTS In order to be successful, a new technology will need to satisfy the airline requirements for its target market. While each segment of aircraft serves a variety of route lengths, there is a clear progression to longer routes for larger aircraft. Based on their current and projected performance, not all new technologies are able to provide the range required for all aircraft segments.

Figure 19- Range profile for Commercial Aircraft segments (source: MHIRJ Aero Advisory Services) H2 Combustion (<2,000 NM) H2 Fuel Cell (<800NM) Battery (<200NM) GEN 1



Cumulative % of Flights

90% 80% 70% 60% 50% 40% 30%

Commuter (<20pax)


Regional (21-100pax) Narrowbody (101-240pax)


Widebody (>240pax) M

M 00 NM <1 10 0N M <1 20 0N M <1 30 0N M <1 40 0N M <1 50 0N M <1 60 0N M <1 70 0N M <1 80 0N M <1 90 0N M <2 00 0N M <1 0


<9 0









<8 0


<7 0


<6 0


<5 0


<4 0


<3 0



<2 0

<1 0

0N M


Flight Distance

Figure 19 – Range profile for Commercial Aircraft segments (source: MHIRJ Aero Advisory Services) 14

The limited range available with near-term battery technology limits its application to the commuter segment, whereas hydrogen combustion could be suitable for the range requirements of narrowbody aircraft. Aligning the benefits of each technology to the needs of the market segment is crucial to understanding how they will impact aviation sustainability overall.

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4.3. EVOLUTION OF ENERGY DEMAND FOR COMMERCIAL AVIATION 2021-2050 The path to Net Zero consists of multiple technologies and fuels that will be introduced to various segments at different times. In order to compare fuel types, the energy content is expressed in kilograms of kerosene equivalents which can then be converted back to the appropriate units when looking at the impact of the specific fuel type on infrastructure and availability. We can see that continuous improvement will deliver approximately 1/3 of the sustainability improvement with the remainder addressed by a mix of more sustainable fuel options.

FIGURE 1- COMMERCIAL AIRCRAFT KEROSENEEQUIVALENT DEMAND 2020-2050 Commercial Aviation Energy Requirement


Fuel Demand for Industry Growth

2-3% CAGR


Continuous Improvement


-1.5% per year

Sustainable Fuels


Hydrogen Combustion Hydrogen Fuel Cell Electricity SAF

300 200 100 0

Carbon Offsets 2020









Hy drogen F uel Cell

Hy drogen Combustion

Total Fuel Demand

Efficiency Improvement

MAAS Sustainability Forecast


PRIVATE AND CONFIDENTIAL © MHI RJ Aviation ULC or its affiliates. All rights reserved.

Mton equivalent

Net Zero Objective

20 – Commercial Aircraft Kerosene-equivalent 2020-2050 FIGURE 21- Figure COMMERCIAL AIRCRAFT ENERGY DEMAND



Commercial Aircraft Energy Demand

450 400


350 300


250 200

14% 0.5%

Offsets and Carbon Captu Technology required

Hydrogen (FC + Combustion) (20 Mton)

Rapid Technology Adoptio

Electricity (30 GWh)

Small GHG contribution fro Commuter and small RJ m

SAF (280 Mton)

Accelerate Industrialization Ramp-up

95% 1%

150 100



50 0

Kerosene (90 Mton)

5% 2030



*Mton equivalent of Kerosene

Figure 21 – Commercial Aircraft Energy Demand 15

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4.4. SUSTAINABLE AVIATION TIMELINE Sustainable Aviation Fuels will have the biggest impact on the reduction of greenhouse gases as they will represent approximately 2/3 of the energy used by commercial aviation by 2050. The amount of hydrogen used starts to accelerate beyond 2040 while electricity, despite powering a large number of small aircraft, has a small impact on the overall industry carbon emissions due to the small number of ASKs that this segment represents.

Figure 22- Sustainable Aviation Timeline Range (NM)

Energy Source 100%


SAF (Mtoneq 400

80% 300




250 200

800 40%

Regional 200


Commuter 0%


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100 50




Hydrogen FC Retrofit



Figure 22 – Sustainable AviationHydrogen Timeline Battery

Hydrogen FC New Design



SAF Production

Total Green Energy


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2021-2030 In the current decade, the biggest impact on aviation emissions will come from continuous improvement. The replacement of older narrowbodies with Airbus neo, Boeing MAX and Embraer E2 aircraft, combined with operational efficiency improvements as FAA NextGen and EASA SESAR airspace procedures are implemented, will be the major contributors. We will see the ramp-up of SAF availability with several airlines, including the OneWorld group, committing to 10% SAF use by 203011. This will be a very exciting time as new technology aircraft enter into service. We will see the first battery-electric commuter aircraft, the first AAMs and the first hydrogen fuel cell retrofits, although sightings will be rare with a minimal immediate contribution to sustainability.

2031-2040 Next decade will see the implementation of the most promising technology that is under development today. New engine technologies such as the Rolls Royce UltraFan and the CFM RISE, will deliver a further 20% efficiency improvement along with the potential to burn alternative fuels such as hydrogen. More electric systems will be increasingly common due to their efficiency advantage, leveraging the development of electric powertrains on smaller aircraft. More radical aerodynamic improvements, such as truss-braced wings and higher aspect ratio wings, will be introduced on new models. SAF will become widely available and take over as the primary contributor to reducing greenhouse gases. Carbon offsets will be used extensively, providing the subsidies for SAF to become cost-competitive with kerosene. Battery developments will lead to increased range capability and the rapid expansion of AAM and commuter aircraft markets. The first new aircraft designs that are optimized to fully leverage the benefits of hydrogen fuel cells will enter into service. The first hydrogen combustion aircraft will also enter into service as the hydrogen market starts to emerge.

2041-2050 Aviation is in the home stretch to reach Net Zero carbon. The world has evolved and all new road vehicles are now electrified. AAMs are commonplace and the availability of clean, quiet battery and fuel cell-powered aircraft has led to a boom in regional aviation as these aircraft can access small, local airfields without disturbing the neighbors. SynFuel production has started to ramp up, ensuring that there is enough SAF to meet the demand of the in-service fleet and the challenging widebody market. Hydrogen combustion is providing a zero-carbon solution for the narrowbody market and improvements in aircraft efficiency have lessened the penalty from the greater storage volume that hydrogen requires.

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4.5. A NOTE ABOUT CARBON OFFSETS Until the production of SAF can meet the demand of conventional aircraft, there will continue to be a need for kerosene. As governments and society demand lower carbon emissions (such as the EU Fit for 55 program), carbon offsets will be key to bridging the gap until technical advances and the development of low-carbon fuels become widely available. For example, many countries have already implemented carbon trading schemes whereby carbon offsets can be invested into carbon capture, sustainable research and development or industrialization of low carbon fuels. Several airlines also offer their own voluntary carbon offset programs which enable passengers to purchase offsets to compensate for the carbon emissions generated by their flight.

Figure 23 – Aviation carbon offsetting voluntary programs (Source: IATA)

The challenge with offset programs is ensuring that the credits are properly recorded and accounted for and that the projects funded deliver real offset benefits. To this end, IATA provides guidelines for airlines wishing to offer their voluntary offset programs as well as a mechanism that is audited through Quality Assurance Standard (QAS) to provide certification and validation12.

Figure 24 – Like many other airlines, Qantas offers passengers a scheme to compensate for their flight-related carbon footprint

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5.1. COMMUTER SEGMENT Commuter aircraft are powered by turboprop engines and carry less than 20 passengers. They consist of both pressurized and unpressurized models with single and multiple engine configurations. Many of these aircraft are designed under Part 23 and typically used for on-demand and charter as well as scheduled operations for flights less than 200nm to access small or remote airports. The first implementation of zero-carbon fuel in commercial aviation will take place in the commuter segment. In fact, the MagniX eBeaver was the first battery-powered commercial aircraft to fly in December 201913. There are several battery-electric aircraft programs with plans to enter service before 2030. These include modification of existing airframes with battery power such as the 9-passenger Tecnam P-Volt14 as well as clean sheet designs such as the 19-seat Heart HS-19.

Figure 25 – Heart ES-19 with United Airlines livery

So far, the aircraft manufacturers have secured over 700 commitments from airlines such as United Airlines, Wideroe and Finnair. These aircraft will be used on very short routes where they will replace older turboprop and piston aircraft. They are less complex with mostly conventional designs, which provides a relatively straightforward path to certification. As battery technology improves and range expands, we expect that market demand will increase. Hydrogen fuel cell-powered aircraft are expected to enter into service in the commuter segment by 2030 as retrofit kits for existing aircraft. ZeroAvia flew the first hydrogen fuel cell powered aircraft, a 6-seat Piper M-class, in September 202015. The adoption of this technology will be slower than for batteryelectric propulsion as it will require the development of new aircraft designs to take full advantage of the range and performance benefits of the fuel cells. Additionally, it will take time for the cost of hydrogen to become competitive and the infrastructure to develop. As a result, battery electric is expected to be the preferred solution over the forecast timeline.

Figure 26 – Hydrogen fuel-cell modified Piper Matrix

SAF will be used for in-service aircraft, however we expect that the lower cost of electricity and the maintenance cost advantage of the electric propulsion systems will motivate operators to consider new green technology, leading to rapid replacement of older models.

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A minimum of

5% SAF 2% Battery 1% H2 Fuel Cell


A minimum of

39% SAF 22% Battery 2% H2 Fuel Cell

2035 2030

A minimum of

2% SAF 0% Battery 0% H2 Fuel Cell

46% SAF 42% Battery 12% H2 Fuel Cell

2045 2040

A minimum of

A minimum of

17% SAF 12% Battery 1% H2 Fuel Cell

2050 A minimum of

54% SAF 32% Battery 7% H2 Fuel Cell

Figure 27 – Commuter Fleet Forecast by Fuel Type


5.2. REGIONAL SEGMENT Regional aircraft consist of a mix of turboprop and turbofan aircraft with 20 to 100 seats. They are typically used to provide feed to major hubs as well as point-to-point service on thin routes up to 800nm. They are usually operated by small regional airlines or under Capacity Purchase Agreements (CPA) for mainline operators. The regional segment is the most diverse group and can be addressed by many different sustainable solutions depending on the specific market requirements and how the technologies evolve over the next decades.

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Regional airlines play a vital role in linking smaller communities to the outside world, in most cases, they provide the only scheduled air transportation service. Whether it is for business or leisure, regional aircraft are the only practical solution where the number of travelers is low and the locations are remote. The promise of clean, quiet, environmentally sustainable aircraft will ensure that these communities remain connected and are able to thrive. This is especially true in the post-Covid world where we see a trend of people choosing to work from home and re-locating to smaller communities that offer a lower cost of living and a more relaxed lifestyle.

% of all scheduled passenger flights in 2020 operated by regional airlines.

% of U.S. airports with scheduled passenger service to which regional airlines provide the only passenger air service.

Figure 29 – Impact of Regional Airlines (source: RAA16)

Hydrogen fuel cells should be in service by 2030 with both ZeroAvia and Universal Hydrogen having secured a combined 100+ commitments for ATR and Dash-8 retrofit kits from several different airlines including Alaska Airlines, Icelandair and Air Nostrum. These kits will be a vital step towards the maturation of the fuel cell technology for aviation use and the developing robust cryogenic hydrogen storage systems. There are several other companies also tackling these issues including MTU, Airbus and research institutes like DLR. The launch of new aircraft designs by the second half of the 2030s should increase the acceptance of hydrogen fuel Figure 28 – Alaska Airlines agreement with ZeroAvia for conversion of Dash 8-400 to hydrogen fuel cell propulsion cell models. With the development of next-generation battery technology offering greater range, we would expect to see some smaller regional aircraft using battery-electric propulsion by the second half of the 2030s. This may be appealing in smaller markets where it is easier to secure electric charging than hydrogen infrastructure. Hydrogen combustion could also be suitable for the regional aircraft market, especially for regional jets that require the speed and range that turbofan engines provide. Embraer presented a 35-50 seat concept powered by a hydrogen gas turbine as part of their Energia family of future aircraft17. The ultimate split between these fuel sources depends on how the various technologies develop as well as the evolution of market perception over time.

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The early implementation of new clean and quiet technology could play a key role in regaining a more positive public image. It would not be surprising to see many airlines re-thinking their networks and deploying green regional aircraft to augment their domestic and regional footprints. In some regions, it could enable commercial aviation to recapture market share from other modes of transportation, such as trains.


5% SAF 0% Battery 1% H2 Fuel Cell 0% H2 Combustion


39% SAF 1% Battery 12% H2 Fuel Cell 1% H2 Combustion

2035 2030

A minimum of

A minimum of

2% SAF 0% Battery 0% H2 Fuel Cell 0% H2 Combustion

52% SAF 6% Battery 32% H2 Fuel Cell 11% H2 Combustion

2045 2040

A minimum of

A minimum of

17% SAF 0% Battery 4% H2 Fuel Cell 0% H2 Combustion

2050 A minimum of

54% SAF 3% Battery 22% H2 Fuel Cell 6% H2 Combustion

Figure 29 – Regional Fleet Forecast by Fuel Type 18

5.3. NARROWBODY SEGMENT Current narrowbody aircraft are all twin turbofan designs with 100-240 seats, operating mostly on routes less than 2,000nm, although they do serve longer thin routes as well. This is the largest segment of the commercial aircraft market and is the cornerstone for low-cost operators. They dominate the major airports all over the world. Models are provided by the duopoly of Boeing and Airbus with Embraer offering some smaller types. COMAC C919 and Irkut MC-21 are newcomers currently under development. The range and speed required for narrowbody jets are consistent with hydrogen combustion. These aircraft will be clean sheet designs with added space in the fuselage dedicated to hydrogen storage. Novel airframe designs such as the blended wing body are also being considered to maximize efficiency and package fuel storage.

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Clean sheet aircraft of this size cost several billions of dollars to develop, making it difficult for new players to enter the market, it also extends the development timeline, especially when new technologies are integrated. Consequently, we do not expect to see these aircraft enter service until the end of the 2030s or early 2040s. However, the size of the narrowbody segment and its impact on sustainability will lead to a rapid ramp-up in production and have a significant impact on the overall fuel mix. By the time these aircraft enter into service, the hydrogen economy should have scaled to the point where hydrogen cost and availability are no longer an issue.

Figure 30 – Airbus ZEROe hydrogen-powered narrowbody aircraft concept18

SAF will continue to be important due to the very large installed base of legacy aircraft.

Figure 31 – Narrowbody Fleet Forecast by Fuel Type

5.4. WIDEBODY SEGMENT Today, the widebody segment is the exclusive domain of Boeing and Airbus with large aircraft accommodating more than 240 passengers and offering an intercontinental range. These aircraft feature multiple classes of service and are powered by the largest turbofan engines. They also carry substantial cargo in their under-floor holds. This segment will be the hardest to abate due to its demanding performance requirements. The current in-production fleet consists of new generation designs which are not expected to sunset until well beyond the 2030s and, likely 2040s. It is possible that we could see hydrogen combustion in the widebody segment start to appear by 2050 possibly in a revolutionary design. Until this time, SAF will provide a Net Zero solution, especially when combined with the efficiency improvements of next-generation engines and aerodynamic enhancements.

Figure 32 – Widebody Fleet Forecast by Fuel Type

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5.5. A NOTE ON ADVANCED AIR MOBILITY There is a new market segment that is generating a lot of excitement and investments. The Advanced Air Mobility (AAM) models (also known as Air Taxi or eVTOL) typically have 4 to 6 seats and a range of approximately 100nm or less and are intended for urban transportation. These vehicles are introducing many innovative technologies and configurations and are promising clean, quiet, sustainable transportation. Most of these models use battery-electric propulsion and we expect these developments to be incorporated into the commercial aviation market starting with the commuter segment.

Figure 33 – Gol placed a commitment for 250 Vertical Aerospace VA-X4 AAM aircraft19

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It goes without saying that addressing the sustainability challenge in aviation will require a tremendous effort by all impacted stakeholders. The nature of the aviation business is highly complex with many competing requirements and limitations such as: aircraft performance, safety, reliability, regulatory, economic, not to mention the global framework of aviation that necessitates the various requirements of transborder travel. Each member will have a role to play.

6.1. AIRLINES As the “face of aviation”, airlines are the public interface with the aviation business. They are also the most impacted by the need for sustainability, whether it is from the higher cost of low-carbon fuel or the environmental activism such as flygskam. Airlines can drive change through their actions.

Optimize operations: Reducing fuel burn not only increases sustainability, but also reduces cost. Programs such as Skybreathe© by OpenAirlines can achieve substantial fuel savings with minimum investment and the savings can be applied to the entire fleet immediately.

Optimize fleets: The use of more modern fuel-efficient aircraft reduces Greenhouse Gas emissions and provides a superior passenger experience. As soon as they become available, adopting battery-electric or hydrogen fuel cell solutions on regional fleets could be an efficient way to expand market reach while presenting a greener public image. Optimizing the network to fully leverage the capabilities of the fleet will also deliver benefits immediately.

Engage passengers: Airlines are in a unique position to mobilize public action. Many passengers are motivated by the lowest ticket price when making travel decisions whereas the adoption of new, cleaner aviation technology will require financial investments, with a corresponding impact on ticket prices. Encouraging passengers to offset their carbon footprint through easy-to-use programs that are prominently displayed throughout the purchase cycle can help raise the visibility of actions being taken to decarbonize aviation. Qantas, with their “Fly Carbon Neutral” initiative which allows passengers to redeem frequent flyer points to purchase offset credits or Lufthansa with “Compensaid,” are examples of airlines that have incorporated such programs into their booking process. Promoting Net Zero business travel through partnerships such as the one between Alaska Airlines and Microsoft is a way to help other companies achieve their own scope 3 emission targets in line with their environmental declarations. This is another example of how airlines can accelerate the adoption of sustainable travel.

Figure 34 – Lufthansa Compensaid passenger carbon offsetting program (Source. Lufthansa20)

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Prepare for the future: A clear sustainability policy supported by concrete actions and incorporated into a branding strategy will prepare an airline to address evolving challenges from a position of strength. Airlines can pro-actively commit to target levels of SAF usage, such as the pledge by Oneworld member airlines to use 10% SAF by 203011. Another example is the incorporation of zero-carbon aircraft into the fleet, such as United Airlines’ order of Heart HS-19 or the Wideroe commitment for Tecnam P-Volt aircraft14. Air New Zealand has even produced a Product Requirement Document for aircraft manufacturers which states their specification for zero-emission aircraft21.

6.2. AIRPORTS In coordination with IATA, the Airport Council International (ACI), representing over 2,000 airports worldwide, has also set a goal of achieving Net Zero carbon emissions by 205022. This objective will be adopted by individual airports voluntarily and applies to scope 1 and scope 2 emissions; however, airports play an important role in the sustainability of aviation both directly and indirectly. As new fuel sources such as SAF and hydrogen are introduced to the aviation market, airports will need to develop the necessary support infrastructure. While the incorporation of SAF should be relatively straightforward, until local sourcing is readily available, airports will need to support book-and-claim accounting to provide for airlines that have committed to using SAF. The introduction of hydrogen will require new infrastructure as well as new protocols for fueling aircraft. The ultra-low temperatures required for cryogenic liquid hydrogen will dictate new handling procedures and storage facilities. Initially, tanker truck delivery will be used for the first hydrogen fuel cell and combustion aircraft but depending on the size of the airport and proximity to other industrial uses, pipeline delivery may become a more practical solution as society moves towards a more hydrogenbased economy. At this point, airports will likely find many landside uses for hydrogen as well. The arrival of battery-electric-powered commuter aircraft and AAM aircraft will require the installation of electric charging systems either at the gates or nearby. These will need to be high-energy, fast-charging systems to enable aircraft to achieve sufficient utilization. There is already a movement for airports to upgrade their existing diesel-powered ground service equipment to battery-electric models. These will require similar charging infrastructure to that required for the aircraft and will give those airports making the change, a head start. Aircraft connections for ground power and conditioned air supplied at the gate mean that aircraft do not need to use their APU, reducing emissions and noise while parked. Additionally, some steps can be taken to manage aircraft traffic to minimize emissions such as implementing Controller Pilot Data Link Communications – Departure Clearance (CPDLC-DCL) so that aircraft spend as little time as possible taxiing and waiting to depart. To prepare for these infrastructure requirements, airports will need to have a clear, and customized view of the energy mix that will be required in five, ten and twenty years. The arrival of clean, quiet and environmentally sustainable commuter and regional aircraft will bring new opportunities to city center airports. By eliminating the noise and emissions it will also eliminate most of the objections that come from local neighborhoods and remove barriers to increasing air traffic. This means more convenience for travelers, shorter commutes to the airport and greater connectivity at the local level. We can expect traffic to increase at smaller airports that are currently under-utilized for commercial traffic and re-direction of domestic travel away from large international hubs to small local and city center airports.

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6.3. AIRCRAFT MANUFACTURERS AND SUPPLIERS Each aircraft program is supported by hundreds of Tier 1 and thousands of sub-tier suppliers working together and dependent on each other. Aircraft design is likely to change due to new requirements for fuel storage, new powerplant configurations and aerodynamic step-changes. The details are still under development; however, what is certain is that these designs will require greater integration of aircraft and engine systems than is the case today. Aircraft and engine manufacturers, along with system providers, will have to work even more collaboratively and intimately to achieve the necessary optimization. There are currently many studies taking place to identify the most promising technologies either through universities (e.g. DLR and Delft), government-sponsored initiatives (e.g. EU Clean Sky23 and UKRI Future Flight Challenge) or aircraft manufacturer-sponsored programs (Boeing ecoDemonstrator 24 and Airbus UpNext 25 ). The technical feasibility and potential benefit of each of the projects will be assessed and those that are the most promising will find their way into production. Figure 35 – Boeing 787 ecoDemonstrator flights using a blend of SAF There are also many start-up companies in the commuter aircraft and AAM market segments that are developing revolutionary concepts that could dramatically change the aviation industry. Historically it has been very difficult for new players to enter the aviation market and there is a long list of companies that have eventually succumbed to the financial burden of launching a new program. It will take revolutionary ideas to conquer the sustainability challenge and we expect those start-ups with the best solutions to eventually partner with the incumbents to adopt the new technologies and spread them through the industry. Economics can be a powerful accelerant for the adoption of new technology as the aviation industry typically operates with very small margins. Therefore, a new technology that provides a substantial saving to operators either through lower cost of energy, lower maintenance cost or lower ownership cost, in addition to the sustainability benefit, will provide an important catalyst for upgrading the existing fleet.

6.4. GOVERNMENTS Governments need to provide the leadership, guidance and vision to support sustainability. ICAO has been proactive in setting industry targets and providing a unified global vision; however, it is up to individual governments to define the policies and mobilize action. There are two main levers through which policy can increase sustainability: increase supply and motivate demand. Considering the near-term challenge to increase the availability of SAF, subsidies for investment into production industrialization are the most effective path to meet the current need and provide a long-term supply. Some programs have already been initiated in North America and Europe; nevertheless, there is a great opportunity in developing markets where investments will also serve to stimulate the local economy. Rather than adding more punitive taxes on airlines and passengers for GHG emissions, governments should incentivize airlines with tax credits when they take concrete steps to reduce emissions, for example by using SAF, to mobilize broad-based sustainable behavior. Similarly, in order to develop the hydrogen economy, there needs to be an investment in green hydrogen production. Government incentives can also be used to help prioritize and direct BioFuel to aviation as opposed to BioDiesel where other options are available today.

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Multilateral agreements between governments to ensure harmonized rules and regulations across jurisdictions is another important activity. This will create a level playing field and align efforts towards the most productive outcome. Organizations such as ICAO and IATA have been effective at presenting a cohesive message, but it is important to avoid local regulations that lead to less sustainable actions. Change is always difficult and decarbonizing aviation will require change for many stakeholders. The role of governments will be to remove the barriers to change and reduce the friction. By implementing policies that encourage sustainable behavior and reward investments in clean technology, Net Zero aviation can be achieved sooner.

6.5. REGULATORS The adoption of new technologies will require a reworking of certification and operational standards, starting with commuter and regional aircraft. Aircraft and engine certifications, airline operating rules and manuals, flight and ground procedures, maintenance procedures, all will have to be adapted to reflect new requirements. Implementation of regulatory changes is a lengthy process to provide adequate time for comments and revisions. This could end up slowing down the deployment of new fleets while the number of fuel configurations that are under development could also lead to complex rules. One should not underestimate the burden on resources as regulators deal with the emergence of the AAM market, new fuel requirements and an avalanche of aviation start-ups all at the same time. Access to certification review and approval expertise could become a scarce and valuable commodity.

6.6. OTHER STAKEHOLDERS There are many other stakeholders in the aviation ecosystem that will be impacted to a greater or lesser degree by the move to more sustainable aviation. Today, petroleum producers provide over 300Mt of kerosene per year for commercial aviation. A switch to SAF will redefine their business model. Initially, SAF was provided by new suppliers; however, the incumbents are quickly coming on board as they see that this is the future and they do not want to be left behind. Implementation of FAA NextGen and EASA SESAR airspace modernization will deliver important operational savings. It has been estimated that up to 10% fuel savings could be achieved for intra-European flights as a result of more efficient routings26. Rapid implementation of these measures will have an immediate impact on the local carbon emissions. Finally, many stakeholders – such as financiers, lessors, airlines, airports, etc. – will have to define or adapt their ESG policies with a focus on operating newer, greener aircraft. This is increasingly becoming a must to attract financing, satisfy investors and secure new business.

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It is possible for commercial aviation to achieve Net Zero by 2050, but there is no silver bullet to reach this target. It will require the cooperation of all the stakeholders: airlines, governments, aircraft manufacturers, airports, air traffic management and fuel suppliers, to name a few. There are simple operational improvements that can be implemented today that will yield results immediately, a new technology that can be incorporated incrementally as older aircraft are retired and new fuel sources that will decarbonize future flying. We will see the incorporation of new technologies deployed first on local and regional flights and these small aircraft will be the incubators for battery-electric and hydrogen fuel cells that mature the technology for broader implementation. Different solutions will be more appropriate for different markets and the order could change as technologies mature. However, it is the industrialization of SAF that will achieve the biggest impact on decarbonization quickly, because it can be used with existing in-service aircraft and is the only solution for narrowbody and widebody aircraft in the short term. Since these aircraft are responsible for the vast majority of the carbon emissions from commercial aviation, this needs to be the priority for the aviation industry now.

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To achieve the target of Net Zero Carbon by 2050, aviation will need to overcome many challenges:

Certification: The introduction of new technologies requires extensive validation to meet the guidelines set by the regulatory authorities. This is a difficult, time-consuming but necessary activity to ensure that the levels of safety society demands are maintained. The key to success will be a deep understanding of the regulatory process and the ability to find the most efficient pathway to demonstrate compliance.

Acceptance: How will each of the stakeholders view the new technologies? We can expect that there will be some friction and resistance to change, undoubtedly not everyone will share a common view on the path forward. Yet, we are living in unprecedented times and there is a willingness to take action. We must leverage the momentum to implement the most effective decarbonization strategies. Economics: Today each of the new fuels brings added costs, but as the technologies mature there will be savings. Governments will play a crucial role in facilitating these developments and providing incentives for early adopters that will pave the way to a more sustainable future. Solid knowledge of aircraft development, airline industry and government policies will be critical to overcoming the hurdles and achieving success; for those who do, the future is full of potential.

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MHIRJ AERO ADVISORY SERVICES Our solutions supporting sustainability initiatives include:

Market trends & strategic market developments: Forecast of market demand based on changes in external factors such as scope clause agreements, new regulations and governmental policies. Fleet and network impact analysis and contingent identification of market challenges and opportunities. Aircraft competitive assessments: Identification of product/aircraft strengths and weaknesses relative to competition and market needs, evaluation of the market potential for new aviation products or services.

Airport competitive assessments: Quantification of aircraft-related energy mix requirements over time. Unique “behavioral” traffic forecast analysis at country or airport level, aircraft rotations forecast.

Product strategy: Evaluation and prioritization of customer requirements for the development of market-matched product features and services. Analysis of product positioning, the definition of top-level aircraft requirements and elaboration of business cases for new developments. Commercial strategy and business development: Definition of effective commercial strategies based on market dynamics. Development of value-selling argumentations and impactful presentations. Support to commercial effort and access to airline decision-makers to secure orders. To find out more, visit our website at or contact us:

MHIRJ AEROSPACE ENGINEERING CENTER A complete and comprehensive engineering team is available for complex or simple product development needs. Full design approval capacity with Design Approval Delegates in all 24 Regulatory Disciplines. Expertise in all aspects of the product development lifecycle: • Concepts, Designs, Testing, Certification, Safety, and Reliability • Flight test planning, analysis and Safety of Flight • Technical Publications – writing, authoring, publishing aircraft manuals • Quality Manufacturing System, Quality Assurance • Manufacturing Certificate, Planning and approved build procedures • Repair, Retrofit, Life Escalation Our full end-to-end service offering is ready to assist in addressing technical challenges. To find out more, visit our website at

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9.1. THE COLORS OF HYDROGEN There are several different types of hydrogen that are categorized by color based on their sustainability. The 3 main types are: 1. Grey hydrogen, obtained by steam reforming of fossil fuels such as natural gas or coal. This process generates CO2 as a waste product and is not sustainable. 2. Blue hydrogen, generated from the steam reduction of natural gas. During this process, natural gas is split into hydrogen and CO2, however, the carbon dioxide is stored or processed industrially with Carbon Capture and Storage (CSS) technology. 3. Green hydrogen, produced on a CO2-neutral basis through the electrolysis of water. During electrolysis, water is split into its constituent elements of oxygen and hydrogen. The required electricity is generated from renewable energy sources such as wind energy, hydropower or solar energy.

Figure A1. The colors of hydrogen (source: EWE)

Production: How much green electricity does it take to produce 20 Mt of green hydrogen? • Electrolysis of 1 kg of H2 requires a 50 kW electrolyzer, 41.4 kWh of electricity and 18 L of water • 20 Mt of H2 requires a 1 TW electrolyzer, 850 TWh of electricity and 360 GL of water (approximately the total global electricity generation by solar photovoltaic panels in 2020, and more than the amount of water that goes over Niagara Falls in a day)

Transportation: • For an 800nm flight, an A320neo would require about 1.4t of LH2, assuming 20% efficiency improvement for the next generation hydrogen aircraft • Each tanker truck carries about 3.5t of LH2 • 1 LH2 tanker truck is required for every 3 narrowbody flights • For 20 Mt H2, that would be about 16,000 trucks per day worldwide. Of course, the split between airports and regions would not be equal.

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9.2. MORE EFFICIENT USE OF AIRSPACE Eurocontrol introduced Free Route Airspace (FRA) in 2008, defined as: “A specified airspace within which users may freely plan a route between a defined entry point and a defined exit point, with the possibility to route via intermediate (published or unpublished) waypoints, without reference to the ATS route network, subject to airspace availability. Within this airspace, flights remain subject to air traffic control.” This direct routing provides the most efficient flight path (great circle distance) between the entry/exit points within a state. Expanding the FRA between adjacent states further extends the benefit by permitting an efficient flight path over a greater area. To date, free route airspace projects are in place across threequarters of the European airspace.

Figure A2. Eurocontrol Free Route Implementation end of 2021 (source: Eurocontrol6)

Advanced Flexible Use of Airspace (AFUA), expands the concept of FRA to allow for the temporary segregation of airspace for military activities based on real-time usage. It provides a cooperative approach to data exchange and leverages Performance Based Navigation (PBN). In 2020 NATS implemented reduced separations standards for the North Atlantic Tracks, taking advantage of the improved surveillance provided by ADS-B to reduce the spacing between aircraft from 40nm to 14nm27. This allows more aircraft to take advantage of the Jetstream and fly the most efficient route at the most efficient speed. In 2021 NATS implemented FRA in the UK. These are some of the changes that will help achieve a 15% reduction in CO2 emissions (vs 2019) by 203028.

Figure A3. Example of AFUA (source: Eurocontrol)

Software tools such as the Intelligent Approach enable ATM to maximize the use of runways and airspace by optimizing aircraft spacing based on aircraft type and live weather conditions. This software has reduced headwind delays by 62%, resulting in lower CO2 emissions. In 2019, over 41,000 tonnes of fuel were burnt in the inner perimeter of Heathrow airport, equating to 130,000 tonnes of CO2, equivalent to 750 Boeing 777s flying from London to New York. It goes without saying that achieving the efficiency gains promised by these and similar projects requires the coordination between many stakeholders, Air Traffic Management, Air Service Network Providers, national regulatory authorities from individual states and others. The key enabler is data that is openly shared and readily available to all users through a common repository (SWIM). The technology is already available and the benefits from its implementation are immediate.

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Advanced Air Mobility


Airport Council International


Advanced Flexible Use of Airspace


Air Navigation Service Provider


Auxiliary Power Unit


Available Seat Kilometer


Air Transport Action Group


Air Traffic Control


Air Traffic Management


Air Traffic Services


degrees Celsius


Carbon Dioxide


Capacity Purchase Agreement


CPDLC-DCL C o n t r o l l e r

Pilot Data Link Communications – Depar ture Clearance


International Association



International Organization



degrees Kelvin




Liquid hydrogen (cryogenic)










MHIRJ Aero Advisory Services






nautical mile


Nitrous Oxides

Tr a n s p o r t Av i a t i o n


Direct Current


Original Equipment Manufacturer


German Aerospace Center



European Union Aviation Safety Agency

Organization of the Petroleum Exporting Countries




European Union


Performance Based Navigation


Electric Vehicle


Proton Exchange Membrane


electric Ver tical Take-Of f and Landing


Quality Assurance Standard


Regional Jet

degrees Fahrenheit


Sustainable Aviation Fuel


Federal Aviation Administration


Single European Sky ATM Research


Gross Domestic Product


Synthetic Fuel

Gen 1

Generation 1


Gen 2

Generation 2

System-Wide Management


Greenhouse Gas






Terrawatt hours


Gigawatt hours


UK Research and Innovation




Video Home System



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IEA. (2021, May). Net zero by 2050 – A Roadmap for the Global Energy Sector. IEA. Retrieved January 31, 2022, from


Hydrogen fuel cells, explained. Airbus. (n.d.). Retrieved January 31, 2022, from

10. Aviation Benefits Beyond Borders. (2020, September). Retrieved February 8, 2022, from 11. Oneworld backs global ambition for sustainable aviation fuel. oneworld. (2021, September 22). Retrieved January 31, 2022, from 12. Aviation Carbon Offsetting Guidelines for voluntary programs. (2020, February). Retrieved January 31, 2022, from 13. Harbour Air and MagniX announce successful flight of world’s first commercial electric airplane. Harbour Air. (2019, December 10). Retrieved January 31, 2022, from 14. Rolls-Royce and Tecnam join forces with Widerøe to deliver an all-electric passenger aircraft ready for service in 2026 -. Tecnam Aircraft. (2021, March 12). Retrieved February 1, 2022, from 15. World first hydrogen-electric passenger plane flight. ZeroAvia. (2020, September 25). Retrieved February 1, 2022, from 16. This is RAA. Regional Airline Association. Retrieved February 1, 2022, from 17. Embraer Energia. Embraer Commercial Aviation Sustainability. (2021, November 23). Retrieved February 1, 2022, from 18. ZEROe. Airbus. (2021, December 10). Retrieved February 1, 2022, from 19. Gol and Grupo Comporte order 250 va-x4 zero emissions aircraft from avolon. Avolon. (2021, September 21). Retrieved February 1, 2022, from 20. Fly CO2-neutral. Compensaid. (n.d.). Retrieved February 1, 2022, from 21. Zero Emissions Aircraft Product Requirements Document. Air New Zealand. (2021). Retrieved February 1, 2022, from 22. Net zero by 2050: ACI Sets Global Long Term Carbon goal for airports. ACI World. (2021, June 8). Retrieved February 1, 2022, from 23. Clean sky 2. Clean Aviation. (n.d.). Retrieved February 1, 2022, from 24. Boeing commits to deliver commercial airplanes ready to fly on 100% sustainable fuels. MediaRoom. (2021, January 22). Retrieved February 1, 2022, from 25. Airbus UpNext. Airbus. (2021, December 10). Retrieved February 1, 2022, from 26. A route to net zero European Aviation - Destination 2050. Destination 2050. (2021, February). Retrieved February 1, 2022, from 27. New separation standard permanently adopted over the North Atlantic. NATS. (2020, December 12). Retrieved February 1, 2022, from 28. Molloy, J., Harris, M., Sandford, B., Harris, I., & Boulton, L. (2021, December 15). Introducing free route airspace into the UK skies. NATS Blog. Retrieved February 1, 2022, from

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