 Ihlefeld flew his first combat missions over Poland and was awarded the Iron Cross 2nd Class () on 26 September 1939.On 10 May 1940, the Battle of France, the German invasion of France and the Low Countries, began and Ihlefeld claimed his first victory of the war on 29 May 1940.The combat took place at an altitude of near Saint-Quentin during the Battle of Dunkirk (26 May – 4 June 1940), the defense and evacuation of British and allied forces from France to England, on a combat air patrol.