In addition to the core Fourteenth Air Force (14AF) structure, a second group, the Chinese-American Composite Wing (CACW), existed as a combined 1st Bomber, 3rd Fighter, and 5th Fighter Group with pilots from both the United States and the Republic of China. U.S. service personnel destined for the CACW entered the China theater in mid-July 1943. Aircraft assigned to the CACW included later series P-40 Warhawks (with the Nationalist Chinese Air Force blue sky and 12-pointed white sun national insignia, rudder markings, and squadron/aircraft numbering) and B-25 Mitchell medium bombers. In late 1944, USAAF-marked P-51 Mustangs began to be assigned to CACW pilots—first P-51B and C series followed by, in early 1945, D and K series. The latter were a reduced-weight versions sharing many of the external characteristics of the D series aircraft including the bubble canopy. All U.S. pilots assigned to the CACW were listed as rated pilots in Chinese Air Force and were authorized to wear the pilot's wings of both nations. One of the known Chinese pilots is Captain Ho Weng Toh of Singapore, the last known surviving Flying Tigers' member in Asia. Captain Ho flew the B-25 bomber, as part of the 1st Bomber Group.