 Complete the following phrase:  The German invasion of Poland began on the 1 September 1939. The invasion began World War II. The Bf 110 Zerstörergeschwader, Zerstörergeschwader 76 ZG 7676th Destroyer Wing and ZG 26 distinguished themselves in the fighter escort role as the long-range bomber pilots from Kampfgeschwader 27 attacked Warsaw airfields to destroy the Polish Air Force. JGr 102, under the command of Hauptmann Gentzen claimed 28 Polish aircraft in aerial combat and a further 50 on the ground. Colonel Stefan Pawlikowskis Warsaw Pursuit Brigade resisted fiercely but lost 17 percent of its fighting strength on 1 September which rose to 72 over the next five days. The unit may have claimed as many as 29 in the air and 78 on the ground. One of JGr 102s missions was providing fighter escort for Ju 87 Stuka dive-bombers in the 