NJG 1 operated all of the major twin-engine night fighters produced by German industry during the war. It fought in notable campaigns, such as the Battle of the Ruhr and Battle of Berlin. By the end of the war, lack of fuel, technical setbacks, lack of training and advances by the Allied powers rendered the night force ineffective from August 1944 until the end of the war in May 1945. NJG 1 was the most successful night fighter wing and had claimed some 2,311 victories by day and night, for some 676 aircrew killed in action.