any of several unconventional aircraft with rotating wing systems, such as the helicopter and autogiro. They may also have rotatable jet systems capable of vertical lift-off and landing in areas that only slightly exceed the overall dimensions of the aircraft.

The first operational VTOL jet aircraft was the British Royal Air Force Harrier; (Harrier) its jet engines are mounted horizontally, with their blast deflected downward to effect vertical thrust for takeoff. It achieved high subsonic speeds in level flight.