Supersonic
Any speed over the speed of sound, which is 1,225 km/h at sea level, is said to be supersonic. Many modern fighter aircraft are supersonic. The Concorde was a supersonic passenger aircraft, but, since its final retirement flight on November 26th 2003, there is no supersonic passenger aircraft in service. Speeds greater than 5 times the speed of sound are sometimes referred to as hypersonic.Charles Elwood Yeager was the first man to break the sound barrier on October 14 1947, flying the experimental Bell X-1 at Mach 1 at an altitude of 45,000 feet.
Hans Guido Mutke claimed to have broken the sound barrier before Yeager, on April 9 1945 in a Messerschmitt Me 262. However, this claim is disputed by most experts and lacks a scientific foundation.