Which type of fuel is most commonly used in commercial jet aircraft?

The most commonly used fuel in commercial jet aircraft is Jet A or Jet A-1 fuels. These kerosene-type aviation fuels are specifically formulated for jet engines and provide excellent performance in the high altitude and varying temperature conditions encountered during flight.

Jet A and Jet A-1 possess properties such as low freezing points, high flash points, and good thermal stability, which are essential for safe and efficient operation of turbine engines. Additionally, these fuels have the right viscosity and density required for the performance and efficiency of commercial aircraft engines, making them the standard choice for the industry.

Other types of fuels, such as Avgas 100LL, are typically used in piston-engine aircraft rather than in commercial jets, which use turbine engines. Biofuels are increasingly being explored as part of a shift toward sustainable aviation, but they currently represent a much smaller percentage of the fuel used in commercial aviation compared to Jet A and Jet A-1. Diesel fuel is not suitable for jet engines and is primarily used in ground vehicles and certain specialized applications. Therefore, the preference for Jet A or Jet A-1 fuels in commercial aviation is well-founded based on performance, safety, and suitability for jet engine operation.