In World War II, he led Jagdgeschwader 51 up to the Battle of Britain and claimed a further six victories during World War II, in the process becoming one of only a few men to score victories and become an ace in both world wars.
In World War II, he led Jagdgeschwader 51 until the Battle of Britain and scored six more victories during the conflict. This made him one of only a few individuals to have won battles and become a fighter ace in both world wars.