Convertiplanes

A convertiplane is defined by the Fédération Aéronautique Internationale (FAI or World Air Sports Federation) as an aircraft which uses rotor power for vertical takeoff and landing (VTOL) and converts to fixed-wing lift in normal flight. In the US, it is further classified as a sub-type of powered lift. In popular usage, it sometimes includes any aircraft that converts in flight to change its method of obtaining lift.