List of X-planes

The X-planes concept officially came into being in 1944, as a joint programme between the National Advisory Committee for Aeronautics (NACA), the US Navy (USN) and the US Army Air Forces (USAAF), in order to pursue research into high-speed aircraft.

[4] X-planes have since accomplished many aviation "firsts" including breaking speed and altitude barriers, varying wing sweep in flight, implementing exotic alloys and propulsion innovations, and many more.

Eventually issues with the Rockwell HiMAT advanced UAV led to a crewed X-plane with forward sweep, the Grumman X-29, which flew in 1984.

[7] Later X-planes supported important research in a multitude of aerodynamic and technical fields, but only the North American X-15 rocket plane of the early 1960s achieved comparable fame to that of the X-1.

[citation needed] X-planes 8, 9, 11, 12, and 17 were actually missiles[8] used to test new types of engines, and some other vehicles were unoccupied or UAVs (some were remotely flown, some were partially or fully autonomous).