The Douglas F5D Skylancer is a development of the F4D Skyray jet fighter for the United States Navy.

Almost every part of the airframe was modified, though the basic form remained the same as did the wing shape, though it became much thinner.

The fuselage was 8 ft (2.4 m) longer and area ruled to reduce transonic drag, being thinner in the region of the wing roots.

The stated reason was that the aircraft was too similar to the already-ordered Vought F8U Crusader, but it is believed by some historians that politics played as big a part; Douglas was already building a very large proportion of the Navy's planes, and giving them the F5D contract would have made it even closer to monopoly.

[3] The project test pilot was Lt. Cmdr Alan B. Shepard Jr. whose report stated that it was not needed by the Navy.

Transferred to NASA in the early 1960s, NASA 212 was used as a testbed for the American supersonic transport program, fitted with an ogival wing platform (the type eventually used on Concorde; data from the program was shared with the European designers),[7] as well as being used as a vision field test platform for the X-20 Dyna-Soar.