After leading No. 126 Squadron on raids into Normandy during the Allied invasion, Plagis took part in many of the attacks on German positions in northern France and the Low Countries that followed over the next few months. He was shot down over Arnhem in the Netherlands during Operation "Market Garden" in September 1944, but suffered only minor injuries and quickly returned to action. He received the Distinguished Service Order on 3 November for his "participat[ion] in very many sorties during which much damage has been inflicted on ... [German] shipping, radio stations, oil storage tanks, power plants and other installations". The citation particularly stressed an engagement in which a small group of Allied fighters led by Plagis had taken on a far superior force of enemy aircraft and shot down five of them, Plagis himself downing two. Plagis was described as "a brave and resourceful leader whose example has proved a rare source of inspiration".