Some smaller aircraft, such as piston-engine planes, may use aviation gasoline (avgas) instead of Jet A-1. Avgas is a type of high-octane gasoline that is specifically designed for use in aircraft engines. It is less dense and has a lower flash point than Jet A-1, making it more volatile and therefore requiring special handling procedures.
In recent years, there has been growing interest in alternative fuels for aircraft, such as biofuels and synthetic fuels. These fuels are derived from renewable sources and offer the potential to reduce carbon emissions and improve the sustainability of aviation. However, these fuels are still in their early stages of development and are not yet widely used in commercial aviation.