Dahl ended the war flying the Messerschmitt Me 262 jet fighter with III./Ergänzungs-Jagdgeschwader 2 (a supplementary fighter unit). On 27 March 1945, Dahl claimed two P-47 Thunderbolt fighter kills. His 129th and last victory was a USAAF P-51 Mustang near Dillingen an der Donau on 26 April 1945. Dahl was promoted to Oberst (colonel) on 30 April 1945. He was taken prisoner of war by US forces in Bavaria at the end of World War II in Europe.
