The Messerschmitt P.1101 was a single-seat, single-jet fighter project developed in response to the 15 July 1944 Emergency Fighter Program, which sought the second generation of jet fighters for the Third Reich. A characteristic feature of the P.1101 prototype was that the sweep of the wings could be changed before flight, a feature further developed in later variable-sweep aircraft such as the Bell X-5 and Grumman XF10F Jaguar. (Source Wikipedia)