The group helped to prepare for the invasion of the Continent by attacking submarine pens, naval installations, and cities in Germany; ports and missile sites in France, and airfields and marshalling yards in France, Belgium, and Germany. During Big Week, 20–25 February 1944, the 447th took part in the intensive campaign of heavy bombers against the German aircraft industry. Supported the invasion of Normandy in June 1944 by bombing airfields and other targets near the beachhead. Aided the breakthrough at Saint-Lô in July and the effort to take Brest in September. Pounded enemy positions to assist the airborne invasion of the Netherlands in September. Also dropped supplies to Free French Forces during the summer of 1944.