15th Air Force was active over Bavaria on 12 September 1944:
"STRATEGIC OPERATIONS (Fifteenth Air Force): In Germany, nearly 330 B-17s and B-24s supported by P-38s and P-51s bomb Lechfeld Airfield, Munich/Allach engine works, and Wasserburg jet aircraft factory."
http://paul.rutgers.edu/~mcgrew/wwii...ml/Sep.44.html