What Is Sustainable Aviation Fuel (SAF)?

What is SAF made from?

Common feedstocks include used cooking oils and waste fats, agricultural and forestry residues, municipal solid waste, and purpose-grown energy crops. A further route, often called power-to-liquid or synthetic fuel, builds jet fuel molecules from captured carbon dioxide and hydrogen produced with renewable electricity. Every production pathway must qualify under established jet fuel standards before it can be flown, and the choice of feedstock largely determines how much lifecycle carbon reduction the finished fuel delivers.

How does SAF differ from conventional jet fuel?

Chemically, very little — that is the point. SAF consists of the same families of hydrocarbons as petroleum-based jet fuel, so it works as a drop-in product, typically blended with conventional fuel and handled by the same tanks, trucks, and aircraft without modification.

The difference is where the carbon comes from. Conventional fuel adds fossil carbon to the atmosphere; SAF recycles carbon that was already in circulation — from waste streams, plants, or direct capture — which lowers net emissions across the fuel's full lifecycle even though it burns the same way in the engine.

Where does SAF fit alongside electric and hydrogen aircraft?

SAF decarbonizes the aircraft that already exist and the long missions that batteries and fuel cells cannot yet serve, because it slots directly into today's turbine engines. Electric and hydrogen propulsion target shorter-range and vertical-lift segments where new airframes are being designed from scratch. The approaches are complementary rather than competing: SAF for the existing fleet and long-haul flying, new propulsion architectures for new classes of aircraft.

Can existing aircraft use SAF?

Yes. SAF is designed as a drop-in fuel that meets existing jet fuel specifications, usually supplied as a blend with conventional fuel. No engine or airframe modifications are required at approved blend levels.

Does SAF eliminate aviation emissions?

No. Burning SAF still releases carbon dioxide at the point of use. The benefit is on a lifecycle basis: because the carbon originates from waste, biomass, or captured sources rather than fresh fossil extraction, net emissions across production and use are substantially lower.

Is SAF the same thing as biofuel?

Not exactly. Biofuels made from plant or waste material are one category of SAF, but the term also covers synthetic fuels produced from captured carbon and renewable electricity. SAF describes the outcome — a specification-compliant jet fuel with a sustainable carbon source — rather than any single feedstock.