Boeing X-51 Waverider - Wikipedia gy demonstrator, hypersonic test aircraft National origin United States Manufacturer Boeing First flight 26 May 2010 Status Flight testing Primary user United States Air Force Number built 4[1] <span>The Boeing X-51 Waverider is an unmanned research scramjet experimental aircraft for hypersonic flight at Mach 5 (3,300 mph; 5,300 km/h) and an altitude of 70,000 feet (21,000 m). The aircraft was designated X-51 in 2005. It completed its first powered hypersonic flight on 26 May 2010. After two unsuccessful test flights, the X-51 completed a flight of over six m