Germany's Me262 was the world's very first operational turbojet-powered aircraft, allowing it to outmaneuver and out-sprint Allied fighter escorts. It actually began development in April 1939, and the eventual result was a fighter that marked a significant leap forward in aircraft design. However, the two Jumo 004 jet engines on each fighter were also a weak point, as turbojets were still in their infancy. The average jet engine's operational lifespan on an Me262 was a mere 12 hours.