A fixe-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 word derives from the Greek αέρας (aéras-) ("air") and -plane. 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.