The aero-engine is also known as a “piston propeller airplane”. It is an airplane powered by a piston aero-engine and propelled by a propeller. Due to the power limitation of the piston engine and the reduced efficiency of the propeller at high speeds, it is only suitable for low-speed flight. Mostly used in light aircraft, ultralight aircraft, etc.-not suitable for military operations. Most piston aircraft were in service before the 1950s, and only a few small planes, ultralights, and unmanned aerial vehicles use this type of engine.