The Me-163 “A” project code named “Project X” started in 1937 under Dr. Alexander Lippisch. It was made for defense purposes using rocket motors. The first Me-163 flew in 1941. There were fuel consumption and engine efficiency problems, which limited its range. In August 1943, the Me-163 B was developed with further enhancements. Production started in July 1944 and a total of 279 were delivered to the Luftwaffe.