During World War II Mehre was in command of the No. 332 Squadron RAF in 1942, and served with the No. 132 Wing RAF from 1943 to 1945. His war decorations included the War Cross with Sword, the Defence Medal 1940–1945, the War Medal, the Haakon VII 70th Anniversary Medal, the British Distinguished Service Order and Distinguished Flying Cross, and the American Distinguished Flying Cross. He was promoted to Major General in 1959.
