The Supermarine Spitfire was a single-seat fighter used by the RAF and many Allied countries in World War II. Produced by Supermarine, the Spitfire was designed by R.J. Mitchell, who continued to refine it until his death from cancer in 1937. The elliptical wing had a thin cross-section, allowing a faster top speed than the Hurricane and other contemporary designs; it also resulted in a distinctive appearance. Much loved by its pilots, the Spitfire saw service during the whole of World War II, in all theatres of war, and in many different variants. More than 20,300 examples of all variants were built, including two-seat trainers, with some Spitfires remaining in service well into the 1950s. It was the only fighter aircraft to be in continual production before, during and after the war.