The Messerschmitt Me 163 Komet, designed by Alexander Lippisch, was a German rocket-powered fighter aircraft. It is the only rocket-powered fighter aircraft ever to have been operational. Its design was revolutionary, and the Me 163 was capable of performance unrivaled at the time. German test pilot Heini Dittmar in early July 1944 reached 1,130 kph (700 mph), not broken in terms of absolute speed until November 1947.

Messerschmitt Me 163
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Sources:
Gunston, Bill & Wood, Tony - Hitler's Luftwaffe, 1977, Salamander Books Ltd., London
Wikipedia - Me 163