At the end of WW2, the Navy and NACA came together to develop a research aircraft for transonic flight. Conceived as a three-part program, it would start with a jet testbed, followed by a mixed-propulsion aircraft, ending in a combat aircraft design. Douglas was contracted to develop a design, which became the D-558-I. The D-558-I was a simple straight-winged design powered by a single J-35 axial-flow turbojet. Following NACA suggestions, the tail was considerably thinner than the wing to avoid simultaneous transonic shocks over the wing and tail, and, in the absence of an ejection seat powerful enough to clear the tail, the entire nose was designed as a jettisonable ejection capsule. Three D-558-Is were ordered, gaining the nickname Skystreak. They were originally painted red, although this was later changed to white to improve optical tracking.
