The Douglas D-558-1 Skystreak is a research aircraft developed in the late 1940s by Douglas Aircraft Company. Designed to explore the transonic flight regime, it was powered by a single Bristol Centaurus radial engine and featured a sleek, streamlined fuselage. The Skystreak was notable for its role in testing aerodynamic concepts and contributed to advancements in supersonic flight. First flown in 1947, the Skystreak was part of a series of experimental aircraft that included the D-558-2 Skyrocket. It achieved significant milestones, including the first jet-powered flight at transonic speeds. The aircraft's design and findings helped shape future developments in military and civilian aviation.