Complex sentence: He served at the Jagdfliegerschule 5 at Wien-Schwechat during 1940/1941 and was Gruppenkommandeur of I./JG 101 from 6 January 1943 to 30 April 1944.
Split into simpler sentences: He served at the Jagdfliegerschule 5 at Wien-Schwechat for the rest of 1940 and into 1941. He was Gruppenkommandeur of I./JG 101 from 6 January 1943 to 30 April 1944.