About this sound Hugo Frey (help·info) (14 April 1915 – 6 March 1944) was a German Luftwaffe ace and recipient of the Knight's Cross of the Iron Cross during World War II. The Knight's Cross of the Iron Cross was awarded to recognise extreme battlefield bravery or successful military leadership. On 6 March 1944, Hugo Frey was killed over Sleen, the Netherlands after attacking a formation of B-17's. He was posthumously awarded the Knight's Cross on 4 May 1944. During his career he was credited with 32 aerial victories including 25 four-engine bombers, all on the Western Front.