Ehlers was promoted to "Leutnant" (second lieutenant) on 1 July 1943. On 7 July, I. "Gruppe" of JG 1 moved to Deelen Air Field. The USAAF targeted the German aircraft industry on 17 August in the Schweinfurt–Regensburg mission. The bombers of the 1st Bombardment Wing headed for the ball bearing factories at Schweinfurt. At 11:50, the Luftwaffe fighters of I. "Gruppe" of JG 1 intercepted a large formation of B-17 bombers in the area of Aschaffenburg. Following the bombers on their southern heading, Ehlers shot down two B-17 bombers. That day, the commander of 2. "Staffel" of JG 1, "Leutnant" Hans Feustel, was wounded in combat. In consequence, Ehlers was appointed "Staffelkapitän" (squadron leader) of 2. "Staffel" the following day.