The Messerschmitt Me 263 was a rocket-powered fighter aircraft developed from the Messerschmitt Me 163 towards the end of World War II. Three prototypes were built but never flown under their own power as the rapidly deteriorating military situation in Germany prevented the completion of the test program.
First unpowered flight of the Me 263 V1 was in February 1945. Several more unpowered flights took place that month. The biggest problem had to do with the center of gravity which was restored with the addition of counterweights. Eventually the production aircraft would have repositioned the engine or the landing gear installation to solve this problem. The landing gear was still non retractable at that time. The results of those first flights was that the aircraft gave a "ziemlich fertigen Eindruck", meaning that it seemed to be ready.
Test flights were later stopped because of fuel shortages for the Bf 110 towplanes. As the Me 263 was not a part of the "Fuhrernotprogramm" (Fuhrer's Emergency Programme), it was difficult to get the resources it needed. For the time being the plane was not expected to enter production but further development was allowed.
The V2 and V3 were not yet ready. The V2 was to get the retractable landing gear and the V3 would have the armament built in. The next month both the V1 and the V2 had the two-chambered HWK 109-509C installed, correcting the center-of-gravity problems. They never flew under their own power but only as gliders.
In April, the Americans occupied the plant and captured the three prototypes and the mock-up. The V2 was destroyed but another prototype ended up in the USA. The rest was handed over to the Russians who then created their own Mikoyan-Gurevich I-270 interceptor.