The ubiquitous Vought OS2U Kingfisher was the US Navy's standard scout and observation floatplane of World War II, serving from land bases and (especially) shipborne catapult launchers such as those found on battleships and cruisers. It was the first monoplane aircraft designed by Vought following numerous earlier biplane designs, and featured some revolutionary new construction techniques such as spot welding in addition to an interchangeable wheeled undercarriage in place of the central float and outriggers. Besides its standard role as a scout, it also operated prominently for artillery spotting, dive bombing, air-sea rescue, anti-submarine warfare (ASW), liaison, and other utility duties in the Pacific, Mediterranean, Atlantic, and Indian oceans. Among its most celebrated accomplishments were the rescue of World War I ace Eddie Rickenbacker following a crash in the Pacific, as well as the daring recovery of ten downed pilots by Lt. John A. Burns off Truk, shuttling his aircraft to a rescue submarine without taking off (with the pilots hanging on the wings). Besides the USN, Kingfishers were flown by a number of other navies including Argentina, Australia, Chile, the Dominican Republic, Mexico, Uruguay, and the UK.

First flight of the prototype XOS2U-1 took place on 20 July 1938 with production units designated OS2U-1 entering service in the summer of 1940. The improved OS2U-2 was the first to be built in significant numbers and included a number of equipment changes while the OS2U-3 was the most widely produced variant with increased fuel capacity and armor for all crew members. An equivalent version was known as the OS2N-1, the designation reflecting the fact that these aircraft were built by the Naval Aircraft Factory in Philadelphia rather than by Vought.