By 1941, the career of the Spitfire is well underway and the RAF has a powerful aircraft with the Mark V that exceeds all expectations. Yet the RAF is already preparing for its successor and new versions are being considered to keep the fighter a step ahead of the opponent. After the Mark VI, VII and VIII were produced in limited numbers, it is the Mk IX, commissioned urgently in the summer of 1942, which becomes the most famous Spitfire. Manufactured until the end of the war and used on all fronts, this aircraft became the standard fighter of the RAF and was widely exported, particularly after the end of hostilities. The latest version of the Spitfire, the Mark XVI, fitted with a Rolls Royce Merlin engine, is actually a Mk.IX equipped with an engine produced by Packard in the United States. Commissioned in 1944, this version introduced for the first time the "glass bubble" on the Spitfire and was used by the RAF until the fifties, replacing the Mk IX and pending the commissioning of the first jets in frontline squadrons.