In February 1940, "Hauptmann" Falck was appointed "Gruppenkommandeur" of I. "Gruppe" of "Zerstörergeschwader" 1 (ZG 1—1st Destroyer Wing), based at Düsseldorf. The "Gruppe" was relocated to the Baltic coast in April and on 9 April, Falck led the unit during the invasion of Denmark. He recorded his seventh (and final) victory, shooting down a Danish Fokker D.XXI taking off from Værløse. On the night of 30 April and 1 May, 50 RAF Armstrong Whitworth Whitley, Vickers Wellington and Handley Page Hampden bombers attacked Luftwaffe airfields in Norway. Falck, his comrade from "K 31" Radusch, "Oberleutnant" Werner Streib, and another pilot, followed the bombers shortly before sunup on their flight back to England. The pilots attacked the bombers without claiming any aerial victories. Following this encounter, Falck submitted a comprehensive tactical report on his night interception ideas and experiences to the "Reichsluftfahrtministerium" (RLM—Ministry of Aviation). Shortly after, "Generaloberst" Erhard Milch, at the time a state secretary in the RLM and temporary commander of "Luftflotte" 5 (Air Fleet 5), visited Falck and discussed his ideas personally with him.