To rectify the aircraft shortage, from 7 April to 13 May 176 F-4s and 12 F-105 Thunderchiefs were transferred from air bases in the Republic of Korea and the continental U.S. to Thailand during Operation "Constant Guard" I-IV. Between 5 February and 23 May, the Strategic Air Command (SAC) reinforced Guam during Operation "Bullet Shot" with a further 124 bombers, bringing the total available in-theater to 209. The Seventh Fleet was also beefed up by the addition of five aircraft carrier groups, including those of the , , , , and . This made five carriers available at any one time to conduct aerial operations. The Republic of Vietnam Air Force (VNAF) at this time consisted of nine squadrons of A-1 Skyraiders, A-37s, and F-5 Freedom Fighters, a total of 119 strike aircraft. There were also two squadrons of AC-47 or AC-119 fixed-wing gunships, totaling of 28 aircraft.