When World War II began, the Adam family were German citizens and could have been interned as enemy aliens. Adam was able to join the Pioneer Corps, a support unit of the British Army open to citizens of Axis countries resident in the UK and other Commonwealth countries, provided they were not considered a risk to security. Adam was seconded to design bomb shelters. In 1940, Adam successfully applied to join the Royal Air Force Volunteer Reserve as a pilot. Adam was trained as a pilot by British actor Michael Rennie, and was one of only three German-born pilots in the wartime RAF. As such, if he had been captured by the Germans, he was liable to execution as a traitor, rather than being treated as a prisoner of war. FLIGHT Lieutenant Adam joined No. 609 Squadron at RAF Lympne on 1 October 1943. He was nicknamed “Heinie the tank-buster” by his comrades for his daring exploits. The squadron flew the Hawker Typhoon, initially in support of USAAF long-range bombing missions over Europe. Later they were employed in support of ground troops, including at the battle of the Falaise Gap, in Normandy after D-Day. In 1944, his brother Denis joined No. 183 Squadron, joining Adam in No. 123 Wing.