On 11 July 1943, Tucker, who was by now a full colonel, led his troops in the Allied invasion of Sicily. There the American ground and sea forces, mistaking the 504th's aircraft for enemy planes, fired on the formations, resulting in the catastrophic loss of 23 aircraft, numerous casualties, and the scattering of troops all over the island. Tucker also led the 504th PIR during the Italian Campaign at Salerno and Anzio, at Nijmegen during Operation Market Garden, and during the Battle of the Bulge. Due to the number of casualties sustained during the fighting in Italy, Tucker and the rest of the 504th did not participate in the Allied invasion of Normandy, instead remaining in England.