Question: What is the name of a German rocket-powered fighter aircraft designed by Alexander Lippisch, the original version being the first to exceed 1000km/h and the subsequent version, known as the Me 263 Scholle having had 3 prototypes, non of which were ever flown?
Sentence (from "Messerschmitt Me 263"): 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.
Relevant evidence: Yes