The Me-163 �Komet� ended up being the only operational rocket-powered fighter aircraft during WWII. The Me-163 �A� project code known as �Project X� started in 1937 under Dr. Alexander Lippisch. It had been created for protection purposes utilizing rocket engines. Initial Me-163 flew in 1941. There were fuel usage and engine efficiency issues, which limited its range. In August 1943, the Me-163 B was created with further improvements. Production started in July 1944 and a complete of 279 had been delivered to the Luftwaffe.