An airplane or aeroplane (informally plane) is a powered, fixed-wing aircraft that is propelled forward by thrust from a jet engine or propeller. Airplanes come in a variety of sizes, shapes, and wing configurations. The broad spectrum of uses for airplanes includes recreation, transportation of goods and people, military, and research. Most airplanes are flown by a pilot on board the aircraft, but some are designed to be remotely or computer-controlled. Just for a short history, in 1799, Sir George Cayley set forth the concept of the modern airplane. He was building and flying models of fixed-wing aircraft in 1803, and he built a successful passenger-carrying glider in 1853. Between 1867 and 1896 the German pioneer of human aviation Otto Lilienthal developed heavier-than-air flight. The Wright brothers flights in 1903 are recognized as "the first sustained and controlled heavier-than-air powered flight". Following WWI, aircraft technology continued to develop. Airplanes h