In February 1944, the 8th and 15th Air Forces commenced flying a series of missions against German targets. In due course, the entire operation earned the name "Big Week." It fell to the 15th Air Force on that last day to draw the concentrated attention of Luftwaffe fighter opposition. Some 100 Messerschmitt-109s and Focke-Wolf-190s attacked the 15th Air Force fleet of 176 unprotected heavy bombers in swarms.