A flettner airplane or rotor airplane is an aircraft on which wings are rotating cylinders using the Magnus effect to create lift. The concept has similarity to Flettner rotors used on a rotor ships. Such airplanes were first built by Anton Flettner. The Flettner airplane should not be confused with the cyclogyro, which uses a different aerodynamic effect, but has a similar configuration of rotors.
Although Flettner constructed at least one aircraft there is no record of successful use. A safety concern intrinsic to the concept is that if power to the rotating drums was lost —even if thrust was maintained— the aircraft would lose its ability to generate lift and remain in flight.
Note 1: A tiltwing or tiltrotor aircraft functions as an aeroplane during normal (horizontal) flight and as a helicopter during low-speed flight.
Note 2: For full-size aircraft with powered rotors the rotor is normally tilted to achieve thrust (e.g. in a helicopter). Some toys (e.g. balloon helicopter) do have a powered rotor with no means to tilt the rotor to produce horizontal thrust.