Airplane fuel is an important component of aviation, and there are several types of fuel used in airplanes. Methanol, with 8 letters, is a type of alcohol fuel that is often used in racing cars and some aircraft engines. AVGAS, with 5 letters, is a type of aviation gasoline that is used in piston-engine aircraft. AISLE, with 5 letters, is a type of jet fuel that is used in turbine-powered aircraft.