The Heinkel He 111 was a medium bomber designed by Siegfried and Walter Guenter in the early 1930s in violation of the Treaty of Versailles. The Heinkel became the most numerous and primary Luftwaffe bomber during the early stages of World War II.
The He 111 was used in a variety of roles on every front in the European Theatre throughout the war. It was used as a strategic bomber during the Battle of Britain, a torpedo bomber during the Battle of the Atlantic, a medium bomber and a transport aircraft on the Western Front, Eastern Front and Mediterranean and North African Fronts. It became obsolete, but the failure to design and produce a successor meant the He 111 continued to be produced until 1944, when piston-engined bomber production was largely halted, in favour of fighter aircraft.
The design of the Heinkel He 111 endured after the war in the CASA 2.111. Its airframe was produced in Spain under license. The design differed significantly in powerplant only. The 2.111 continued in service until 1973, when it was retired.