The Martin Marietta X-24 is an American experimental aircraft developed from a joint United States Air Force-NASA program named PILOT (1963–1975).

It made its first, unpowered, glide flight on April 17, 1969 with Air Force Maj. Jerauld R. Gentry at the controls.

The X-24B's design evolved from a family of potential reentry shapes, each with higher lift-to-drag ratios, proposed by the Air Force Flight Dynamics Laboratory.

To reduce the costs of constructing a research vehicle, the Air Force returned the X-24A to the Martin Marietta Corporation (as Martin Aircraft Company became after a merger) for modifications that converted its bulbous shape into one resembling a "flying flatiron"—rounded top, flat bottom, and a double delta planform that ended in a pointed nose.

[4] After learning about a remark by Chuck Yeager that he would like to have some jet-powered lifting bodies for training purposes, Martin designed and built, on their own initiative, two examples of the SV-5J.

)[citation needed] Martin were unable to convince Milt Thompson to fly the SV-5J, even after offering a $20,000 bonus.

The X-24A shape was later borrowed for the X-38 Crew Return Vehicle (CRV) technology demonstrator for the International Space Station.

The X-24B is on public display at the National Museum of the United States Air Force, Wright-Patterson AFB, Ohio.

(1974–75)[5]General characteristics Performance Related development Aircraft of comparable role, configuration, and era