Planning for Operation OVERLORD, the invasion of Normandy, had begun years before and had included the prospect of airborne operations. To control them, Major General Lewis H. Brereton's Ninth Air Force activated the IX Troop Carrier Command in October 1943 under Brigadier General Benjamin F. Giles. However, even before Giles assumed command, it was understood that Williams would be in charge of the operations. He took over on 25 February 1944, bringing with him a number of experienced officers from the Mediterranean. When Giles assumed command, IX Troop Carrier Command consisted of the 50th Troop Carrier Wing, with the 315th and 434th Troop Carrier Groups. The 53rd Troop Carrier Wing arrived from the United States in February followed by the 52nd Troop Carrier Wing from Sicily in March. This brought the IX Troop Carrier Command's strength to three wings with fourteen groups. By the end of May, it had 1,116 crews and 1,207 operational aircraft. In addition, it had 1,118 operational Waco and 301 operational Horsa gliders.