The Messerschmitt Me 262, nicknamed Schwalbe (German: "Swallow") in fighter versions, or Sturmvogel (German: "Storm Bird") in attack versions, was the world's first operational jet-powered fighter aircraft. Design work started before World War II began, but engine problems and top-level interference kept the aircraft from operational status with the Luftwaffe until mid-1944. The Me 262 was used in a variety of roles, including light bomber, reconnaissance, and even experimental night fighter versions. Me 262 pilots claimed a total of 542 Allied kills, although higher claims are sometimes made.