German Komet, WWII rocket-powered aircraft. Illustration of the trajectory of a Messerschmitt Me 163 Komet as it attacks US military aircraft. The Komet was a rocket-powered aircraft flown by the German air force (the Luftwaffe) from 1944. It had first flown in 1941, but required extensive testing before entering operational use. It was the first aircraft to exceed speeds of 1000 kilometres per hour. Around 370 were built, but it was not effective as a military aircraft during the Second World War due to the short duration of its flights. Here, it is attacking a Boeing B-17 Flying Fortress bomber (centre), with a smaller plane at upper right.