Before and during the war, both British and German designers were developing jet engines to power airplanes. The first jet aircraft to fly, in 1939, was the German Heinkel He 178. In 1943, the first operational jet fighter, the Messerschmitt Me 262, went into service with the German Luftwaffe and later in the war the British Gloster Meteor entered service but never saw action – top airspeeds of aircraft for that era went as high as 1,130 km/h (702 mph), with the early July 1944 unofficial record flight of the German Me 163B V18 rocket fighter prototype.