<P> The Bell P - 59 Airacomet was the first American jet fighter to be put into service . It was never used in combat, as was mainly useful as an experimental fighter as its performance was inferior to the piston - engined North American P - 51 Mustang which could reach higher top speeds and had a much greater range . </P> <P> Japan had some experimental models, such as the Nakajima J9Y Kikka, but none saw operational use . </P> <P> The plans for the first operational jet fighter, the Messerschmitt Me 262 Schwalbe were drawn up in 1939, and the airplane first flew under jet power in 1942 . The Me 262 was not operational until 1944, and its effectiveness was crippled by the deteriorating infrastructure of Nazi Germany; the advanced materials needed for its engines were in short supply . Although the Me 262 is often classified as an early straight - wing design, it actually incorporates some features of a slightly "swept wing" design, as it had a leading edge sweep of only 18.5 °, too slight to achieve any significant advantage in increasing the critical Mach number, the speed at which it can fly without encountering control problems due to compressibility . Sweep was added after the initial design of the aircraft for balance reasons, when the engines proved heavier than originally expected, primarily to position the center of lift properly relative to the center of mass . There was originally a 35 ° sweep, proposed by Adolph Busemann, which was not adopted . Despite its late - war debut into production, the winner of Nazi Germany's Volksjäger light fighter competition, the Heinkel He 162 A Spatz . was just about to enter service with the Luftwaffe's JG 1 and even the specialist unit JV 44 at the war's end, but only very isolated engagements with Allied combat aircraft--with JG 1 losing 13 He 162As during April 1945, ten to operational losses not involving combat (the design was still going through its evaluation period) and only a pair of actual losses of He 162As from aerial combat . 320 examples of the He 162A were completed by the war's end, with hundreds more incomplete He 162A airframes in the process of manufacture . </P> <P> World War II ended before jet fighters were common . The United States and the United Kingdom also had jet fighters operational before the end of the war . The British Gloster Meteor twin - engined high speed fighter was used to intercept Germany's V - 1 flying bombs missiles over the British Isles and not deployed for combat over Europe until 1945 but still kept away from occupied territory to prevent the technology being picked up by the Germans or Soviets . By 1946 16 RAF squadrons were equipped with Meteors . The American Lockheed P - 80 entered service in the closing phases of the war and was deployed to Europe but arrived too late to see any combat . </P>

When were the first jets used in war