X-15 Rocket Plane First Free Flight

The North American X-15 was a rocket-powered aircraft operated by the United States Air Force and the National Aeronautics and Space Administration (NASA) as part of the X-plane series of experimental aircraft. The X-15 set speed and altitude records in the early 1960s, reaching the edge of outer space and returning with valuable data used in aircraft and spacecraft design. As of 2013, the X-15 holds the official world record for the highest speed ever reached by a manned aircraft. Its maximum speed was 4,520 miles per hour (7,274 km/h) (Mach 6.72).