Initially pursuing an Army career, he then joined the security police and eventually the Luftwaffe.

Serving in the Luftwaffe as the Commander of Air Region Staffs 17 (Poland), 300 (Denmark), Balkans, and Crete, Andrae took part in the campaigns against Poland, Denmark, the Balkans and Crete, respectively.

[2] This plan never materialized, since in fall 1942, Andrae was assigned to the Reich Air Ministry, leaving the command of Crete to paratrooper General Bruno Bräuer.

Andrae retired from service in May 1943, to be called again for active duty as an artillery General in April 1945 with the 4th Panzer Army.

After the surrender of Germany in May 1945, Andrae was captured by the British and then extradited to Greece to be tried for war crimes he was responsible for while in Crete.