The sound of the part of an aircraft that generates mechanical power. Aircraft engines are almost always lightweight piston engines, gas turbines, or, in small multicopter UAVs, electric motors.
The sound of an internal combustion airbreathing engine that generates thrust by discharging a fast-moving jet of gas. Jet aircraft use such engines for long-distance travel.
The sound of an aircraft propulsion system that converts rotary motion from an engine via a rotating set of blades into forward thrust through the air.