The Supermarine Spitfire is a British single-seat fighter aircraft used by the Royal Air Force and other Allied countries before, during, and after World War II. Many variants of the Spitfire were built, from the Mk 1 to the Rolls-Royce Griffon engined Mk 24 using several wing configurations and guns. It was the only British fighter produced continuously throughout the war, and the Spitfire remains popular among enthusiasts, around 70 remain airworthy, and many more are static exhibits in aviation museums throughout the world.