The HE-111 was one of the most successful medium bombers deployed by the German Luftwaffe in WWII. Designed as a pre-war airliner, the HE-111 served from 1939 to 1945 on every front where German troops were deployed. The HE-111 was used extensively during the Battle of Britain from 1940 to 1941. The long range and rugged design of the HE-111 made the aircraft ideal as a long-range bomber, patrol bomber and at times it was used as a high-speed transport. The Spanish Air Force continued to use up-dated versions of the HE-111 for decades after WWII.