A fixed-wing aircraft is a heavier-than-air craft whose lift is generated not by wing motion relative to the aircraft, but by forward motion through the air. The term is used to distinguish from rotary-wing aircraft or ornithopters, where the movement of the wing surfaces relative to the aircraft generates lift. The more commonly used term is “airplane” (in the US and Canada), or “aeroplane” (in Ireland and Commonwealth nations excluding Canada), which refers to any fixed wing aircraft powered by propellers or jet engines. The spelling “aeroplane” is the older of the two, dating back to the mid-late 19th century.Fixed-wing aircraft may be manned or not; they may be large or tiny; every fixed-wing aircraft is open to being scale modeled by perhaps a smaller or larger mimic fixed wing aircraft. Many fixed-wing aircraft may be remotely controlled or robot controlled.

Fixed-wing aircraft range from small training and recreational aircraft to large airplanes and military cargo aircraft. The word also embraces aircraft with folding or removable wings that are intended to fold when on the ground. This is usually to ease storage or facilitate transport on, for example, a vehicle trailer or the powered lift connecting the hangar deck of an aircraft carrier to its flight deck. It also embraces “variable geometry” aircraft, such as the General Dynamics F-111, Grumman F-14 Tomcat and the Panavia Tornado, which can vary the sweep angle of their wings during flight. There are also rare examples of aircraft which can vary the angle of incidence of their wings in flight, such the F-8 Crusader, which are also considered to be “fixed-wing”.

The two necessities for fixed-wing aircraft are air flow over the wings for lifting of the aircraft, and an area for landing. The majority of new or used aircraft, however, also need an airport with the infrastructure to receive maintenance, restocking, refueling and for the loading and unloading of crew, cargo and passengers. Some aircraft are capable of take off and landing on ice, aircraft carriers, snow, and calm water.

The aircraft is the second fastest method of transport, after the rocket. Commercial jet aircraft can reach up to 900 km/h. Single-engined aircraft are capable of reaching 175 km/h or more at cruise speed. Supersonic aircraft (military, research and a few private aircraft) can reach speeds faster than sound. The speed record for a plane powered by an air-breathing engine is held by the experimental aircraft (NASA X-43), which reached nearly ten times the speed of sound.