Task: Question Understanding
Input (English): Context : Willy Lehnert (9 March 1916 -- 10 July 1975) was a German Luftwaffe bomber radio operator and recipient of the Knight's Cross of the Iron Cross (German: Ritterkreuz des Eisernen Kreuzes) during World War II. The Knight's Cross of the Iron Cross was awarded to recognise extreme battlefield bravery or successful military leadership. 
Question : Which armed forces utilised the service of Willy Lehnert?
Output (English): military branch