By 1972, with Vietnamization at an advanced stage, Da Nang AB was one of only 4 major USAF bases remaining in South Vietnam with the 366th TFW based there. When the Easter Offensive began on 30 March 1972 the USAF moved quickly to build up its tactical fighter strength in Vietnam, on 3 April 9 F-4s were deployed to Da Nang AB as part of Operation Commando Fly, these aircraft were soon joined by an additional 9 F-4s and formed the 35th Tactical Fighter Squadron (35th TFS).