The aviation industry is undergoing a major transformation in response to climate change, fluctuating fuel costs, and the global push for sustainability. Conventional jet fuel, derived from fossil sources, has long been the industry standard, but it contributes significantly to carbon emissions. With international targets to reach net-zero emissions by 2050, aviation companies, researchers, and governments are investing in alternative fuels and propulsion systems.
This article explores the most promising developments in aviation fuel, including Sustainable Aviation Fuel (SAF), hydrogen propulsion, electric and hybrid-electric aircraft, and emerging synthetic fuels. It also examines the key companies leading these efforts and the challenges the industry must overcome.
1. Sustainable Aviation Fuel (SAF)
Sustainable aviation fuel (SAF) is the main term used by the aviation industry to describe a non conventional (fossil derived) aviation fuel. The chemical and physical characteristics of SAF are almost identical to those of conventional jet fuel and they can be safely mixed with the latter to varying degrees, use the same supply infrastructure and do not require the adaptation of aircraft or engines.
SAF is currently the most immediate and practical alternative to conventional jet fuel. Produced from renewable sources such as used cooking oil, agricultural residues, algae, and even municipal waste, SAF can reduce lifecycle carbon emissions by up to 80% compared to fossil fuels.
As the aviation industry works toward net-zero emissions by 2050, finding alternatives to traditional jet fuel is a top priority. One of the most immediate and scalable solutions is Sustainable Aviation Fuel (SAF)—a cleaner alternative that can significantly reduce carbon emissions without requiring major changes to existing aircraft or airport infrastructure.
SAF offers several advantages that make it a key part of aviation’s decarbonization strategy:
1. Providing Environmental Benefits
Relative to fossil fuels, sustainably produced, unconventional, jet fuel results in a reduction in carbon dioxide (CO2) emissions across its life cycle. Carbon dioxide absorbed by plants during the growth of biomass is roughly equivalent to the amount of carbon dioxide produced when the fuel is burned in a combustion engine, which is simply returned to the atmosphere. This would allow the SAF to be approximately carbonneutral over its life cycle.
2. Providing Diversified Supply
The airline industry’s reliance on fossil fuels means that it is affected by a range of fluctuations, such as the changing price of crude oil and problems with supply and demand. SAF is an attractive alternative as its production is not limited to locations where fossil fuels can be drilled, enabling a more diverse geographic supply and a degree of energy security for states and airlines. In theory, a range of SAF feedstocks can be grown or collected in differing conditions around the world, depending on the natural environment, wherever the aviation industry needs it. As is the case with the petroleum industry, there will likely be major producers of SAF feedstock (which will be transported to where it needs to be used), and it is also likely that local smaller scale supply chains will be established.
3. Providing Economic and Social Benefits
Fuel is typically the single largest operating cost for the airline industry. The fluctuating price of crude oil also makes it very difficult to plan and budget for operating expenses long-term. SAF may offer a solution to this problem since its production can be spread worldwide, and across a number of different feedstocks, thereby reducing airlines’ exposure to the fuel cost volatility that comes with having a single energy source. SAF can also provide economic benefits to parts of the world that have large amounts of marginal or unviable land for food crops, but are suitable for growing SAF crops, or which have other sources of feedstock such as municipal waste. Many of these countries are developing nations that could benefit greatly from a new industry such as sustainable aviation fuel production without negatively impacting their local food production ability. On a social level, SAF could stimulate job growth, but also encourage improved waste management strategies as it is not uncommon for waste to be an environmental problem in developing countries. Implementing SAF could provide a mutually beneficial strategy to process waste, while simultaneously reducing CO2 emissions in aviation.
Key Developments in SAF
Airbus and Boeing have both taken significant steps in proving the feasibility of SAFs in commercial aviation. Both aircraft manufacturers have successfully conducted test flights using 100% SAF, showcasing its potential to reduce carbon emissions without requiring major modifications to existing aircraft designs. These test flights serve as a critical milestone in validating SAF as a viable alternative to conventional jet fuels.
United Airlines has emerged as a leader in the airline industry’s transition towards sustainability. The airline has committed to integrating SAF into its operations across its fleet, reducing reliance on fossil fuels. Additionally, United Airlines has invested in sustainable fuel startups such as Fulcrum BioEnergy and Neste, companies that specialize in producing SAF from waste materials and renewable sources. These investments are aimed at scaling up SAF production and making it more economically viable for widespread adoption.
Lufthansa Group has also been proactive in incorporating SAF into its flight operations. The company has been working closely with industry partners to scale up the production and distribution of sustainable fuels. By integrating SAF into its supply chain and operations, Lufthansa is helping to accelerate the transition towards a lower-carbon aviation sector. The airline group continues to advocate for policies and innovations that support SAF development, ensuring a more sustainable future for air travel.
Despite its advantages, SAF still faces major challenges, including high production costs and limited supply. The International Air Transport Association (IATA) estimates that SAF currently accounts for less than 1% of total aviation fuel consumption. Governments and private sectors are working on incentives to increase its production and adoption.
2. Hydrogen-Powered Aviation
Hydrogen is considered a long-term solution for zero-emission aviation. It can be used in two ways:
- Hydrogen combustion: Hydrogen can be burned in modified jet engines, similar to conventional fuel but with no CO₂ emissions.
- Hydrogen fuel cells: Hydrogen can be converted into electricity to power electric aircraft.
Airbus is leading the hydrogen revolution through its ZEROe initiative. In 2020, the company revealed three hydrogen-powered aircraft concepts, aiming for commercial service by 2035. At the 2025 Airbus Summit, held in Toulouse on March 25, Airbus provided a critical update on its ZEROe project, which aims to develop a hydrogen-powered aircraft for commercial service, While Airbus had previously explored multiple hydrogen propulsion concepts, the company has now chosen to focus on a fully electric fuel-cell-powered aircraft.
Despite its potential, hydrogen aviation faces several hurdles, including:
- The need for entirely new airport infrastructure for hydrogen storage and refueling.
- The challenge of producing green hydrogen (made using renewable energy) at scale.
- The larger fuel tanks required, which impact aircraft design and range.
3. Electric and Hybrid-Electric Aircraft
While fully electric commercial jets remain impractical due to battery limitations, electric and hybrid-electric aircraft are making significant progress in regional and short-haul markets. Advances in battery technology, lightweight materials, and electric propulsion systems are driving the development of sustainable aviation solutions.
Hybrid-electric propulsion, which combines conventional jet fuel with electric power, is considered a key transitional technology before fully electric aircraft become viable for larger commercial operations. By reducing fuel consumption and emissions, hybrid-electric systems can provide immediate environmental benefits while leveraging existing infrastructure.
Airbus is investing heavily in hybrid energy research and has partnered with leading aerospace companies like Siemens and Rolls-Royce to develop hybrid-electric systems. The company's EcoPulse demonstrator, developed with Daher and Safran, is an example of ongoing research into distributed hybrid-electric propulsion.
Leading Companies in Electric Aviation
Eviation Alice: A 9-passenger, fully electric aircraft developed by Eviation, completed its maiden flight in 2022. It features a range of approximately 400 nautical miles and is expected to enter commercial service by 2027. Alice is designed for regional air travel, offering lower operating costs and zero carbon emissions.
Rolls-Royce: The company is at the forefront of electric aviation, developing electric propulsion systems and working on hybrid solutions for commercial aviation. Rolls-Royce has successfully tested the "Spirit of Innovation," an all-electric aircraft that set a world speed record for electric flight. The company is also collaborating with partners to integrate hybrid-electric technology into future aircraft.
Heart Aerospace: A Swedish company developing the ES-30, a hybrid-electric regional aircraft with a 500 km (310 miles) range. The ES-30 is designed to accommodate up to 30 passengers and will use a combination of battery power and a fuel-based generator to extend range and enhance operational flexibility. Airlines such as Air Canada and United Airlines have already expressed interest in the aircraft.
4. Power-to-Liquid (PtL) and Synthetic Fuels
Power-to-Liquid (PtL) and synthetic fuels are gaining attention as potential carbon-neutral alternatives to conventional aviation fuels. These fuels are produced by utilizing renewable energy to extract carbon dioxide (CO₂) from the atmosphere and combining it with hydrogen through a chemical synthesis process. The result is a liquid hydrocarbon fuel that can be used in existing aircraft engines without modification.
One of the key advantages of PtL fuels is their compatibility with current aviation infrastructure. Unlike hydrogen or electric propulsion, which require new aircraft designs and fueling systems, PtL fuels can be seamlessly integrated into the existing fuel supply chain. This makes them a promising short- to medium-term solution for decarbonizing aviation while new technologies are being developed.
Several companies and research organizations are leading efforts to advance PtL technology. European startups such as Sunfire and Climeworks are at the forefront of developing synthetic aviation fuels. Climeworks specializes in direct air capture (DAC) technology to remove CO₂ from the atmosphere, while Sunfire focuses on high-temperature electrolysis to produce renewable hydrogen—both essential components in PtL fuel production.
Governments and aviation industry leaders are also investing heavily in synthetic fuel development. The German government has committed significant funding to large-scale PtL fuel production as part of its clean aviation strategy. Similarly, Airbus has partnered with energy companies to explore synthetic fuel applications in commercial aviation, with the goal of reducing the industry's carbon footprint.
Despite its potential, PtL fuel faces significant challenges, primarily related to production costs and energy requirements. The process requires large amounts of renewable electricity to generate hydrogen through electrolysis and to power CO₂ capture technologies. This makes synthetic fuels currently more expensive than conventional jet fuel. However, with advancements in renewable energy capacity, improvements in efficiency, and supportive policies, the cost of PtL fuels is expected to decrease over time.
In addition to aviation, PtL fuels could also be used in other sectors where electrification is difficult, such as shipping and heavy industry. Their ability to store and transport renewable energy in liquid form makes them an attractive alternative to fossil fuels in multiple applications.
As global efforts to achieve net-zero emissions in aviation intensify, PtL and synthetic fuels are likely to play a crucial role in the transition toward sustainable air travel. Continued investment, technological innovation, and policy support will be essential to scale up production and make these fuels a viable alternative to conventional jet fuel.
Challenges and Future Outlook
Infrastructure and Supply Chain Issues
One of the biggest obstacles to the widespread adoption of alternative aviation fuels is infrastructure. Hydrogen, Sustainable Aviation Fuel (SAF), and Power-to-Liquid (PtL) fuels require significant investments in production facilities, transportation networks, and airport storage. Developing these systems is crucial to ensuring a seamless transition to more sustainable aviation fuels.
Cost and Economic Viability
Currently, alternative fuels are significantly more expensive than conventional jet fuel. SAF, for instance, costs approximately three to five times more than traditional kerosene. To bridge this gap, governments and the private sector are implementing incentives, subsidies, and mandates to enhance the competitiveness of sustainable fuels. Reducing production costs and increasing efficiency will be essential for broader adoption.
Policy and Regulatory Support
Governments and aviation authorities play a crucial role in shaping the industry's transition to sustainable fuels. Key policies include:
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EU Fit for 55: The European Union has implemented mandates to increase SAF usage, with a target of 63% SAF by 2050.
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The U.S. Sustainable Skies Act: This legislation aims to provide tax credits and funding to support SAF production and hydrogen aviation research.
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ICAO’s Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA): A global initiative focused on reducing aviation emissions through offset programs and cleaner fuel adoption.
Conclusion
The future of aviation fuel will be shaped by a combination of SAF, hydrogen propulsion, electric and hybrid-electric systems, and synthetic fuels. While SAF presents an immediate solution, hydrogen and electric aviation represent the long-term vision for achieving zero-emission flights.
Leading aerospace companies, including Airbus, Boeing, Rolls-Royce, ZeroAvia, and Universal Hydrogen, are actively driving innovations in sustainable aviation. However, significant challenges remain, particularly in scaling production, reducing costs, and developing the necessary infrastructure to support these alternative fuels.
As governments and industry leaders accelerate efforts toward net-zero aviation by 2050, the coming decades will be crucial in determining whether these emerging technologies can successfully replace traditional fossil fuels and create a cleaner, more sustainable future for air travel.
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