Supersonic aircraft

A supersonic aircraft is an aircraft capable of supersonic flight, that is, flying faster than the speed of sound (Mach 1). Supersonic aircraft were developed in the second half of the twentieth century. Supersonic aircraft have been used for research and military purposes; however, to date, only two supersonic aircraft, the Tupolev Tu-144 (first flown on December 31, 1968) and the Concorde (first flown on March 2, 1969), have ever entered civilian service, both commercially used as supersonic passenger airliners. Fighter jets are the most common example of supersonic aircraft. The aerodynamics of supersonic flight is called compressible flow because of the compression associated with the shock waves or "sonic boom" created by any object traveling faster than the speed of sound. Aircraft flying at speeds above Mach 5 are called hypersonic aircraft. Supersonic speed is defined relative to air speed; higher speeds can be achieved in terms of ground speed when flying in the same direction as fast-moving winds such as the jet stream.