The Douglas F5D Skylancer was a development of the F4D Skyray for the US Navy. It was based on the all-weather variant of the F4D, the F4D-2N.
Because the differences to the F4D became greater, it was realized that the F5D wasn't a variant of the F4D anymore, so that the aircraft was renamed to F5D. The fuselage was completely redesigned and the aircraft was 2.4 m longer than before. Only the design of the wings remained basically the same.
Despite that the F5D was equipped with four 20 mm cannons on the wings, its main weapons were missiles. It was able to carry four AIM-9 Sidewinders or two AIM-7 Sparrow, as well as 72 unguided 51 mm missiles.
All in all about nine test aircraft were ordered and about 51 service aircraft. The first flight took place on 21st April 1956. During the flight the aircraft showed excellent flight performance and met all the requirements or exceeded them. However, after already four aircraft had been build, the US Navy cancelled the program, because the F5D had too many similarities to the earlier Chance Vought F8U Crusader. Some aviation historians believe that this was a political decision, because Douglas produced most of the US Navy's aircraft, so that other manufacturers should get the chance to develop aircraft for the Navy.
The four remaining aircraft were used for military test programs. Two of them were retired in 1962. The other two were delivered to the National Advisory Committee for Aeronautics (NACA), to be used for testing for the supersonic transport program, the results were shared with the Europeans and were used for the Concorde program. One aircraft was retired in 1968. The last one was used for simulation procedures for the X-20 DynaSoar program of the NASA, but which was cancelled in 1970.