In 1943, when he was 16, Joseph Ratzinger was drafted with many of his classmates into the Luftwaffenhelfer program. They were posted first to Ludwigsfeld, north of Munich, as part of a detachment responsible for guarding a BMW aircraft engine plant. Next they were sent to Unterföhring, northwest of Munich, and briefly to Innsbruck. From Innsbruck their unit went to Gilching to protect the jet fighter base and to attack Allied bombers as they massed to begin their runs towards Munich. At Gilching, Ratzinger served in a telephone communications post. On 10 September 1944, his class was released from the Corps. Returning home, Ratzinger had already received a new draft notice for the Reichsarbeitsdienst. He was posted to the Hungarian border area of Austria; Austria having been annexed by Germany in the Anschluss of 1938. When Hungary was occupied by the Red Army Ratzinger was put to work setting up anti-tank defences in preparation for the expected Red Army offensive.