Aviation fuels are petroleum-based fuels, or petroleum and synthetic fuel blends, used to power aircraft. They have more stringent requirements than fuels used for ground use, such as heating and road transport, and contain additives to enhance or maintain properties important to fuel performance or handling. They are kerosene-based (JP-8 and Jet A-1) for gas turbine-powered aircraft. Piston-engined aircraft use gasoline and those with diesel engines may use jet fuel (kerosene). By 2012 all aircraft operated by the U.S. Air Force had been certified to use a 50-50 blend of kerosene and synthetic fuel derived from coal or natural gas as a way of stabilizing the cost of fuel.
Specific energy is an important criterion in selecting fuel for an aircraft. The much higher energy storage capability of hydrocarbon fuels compared to batteries has so far prevented electric aircraft using electric batteries as the main propulsion energy store becoming viable for even small personal aircraft.
As aviation moves into the renewables era, hydrogen-powered aircraft might enter common use. These are zero-emission for CO2 but not for NOx. Cryogenic hydrogen can be used as a liquid at temperatures below 20 K. Gaseous hydrogen involves pressurized tanks at 250–350 bar. With materials available in the 2020s, the mass of tanks strong enough to withstand this kind of high pressure will greatly outweigh the hydrogen fuel itself, largely negating the weight to energy advantage of hydrogen fuel over hydrocarbon fuels. Hydrogen has a severe volumetric disadvantage relative to hydrocarbon fuels, but future blended wing body aircraft designs might be able to accommodate this extra volume without greatly expanding the wetted area.
Even if finally practical, the industry timeline for adopting hydrogen is fairly lengthy. An alternative to conventional aviation fuel available in the near term is aviation biofuel, sometimes termed sustainable aviation fuel (SAF).