The 21st Tactical Air Support Squadron (21st TASS) was a U.S. Air Force forward air control

Forward air control

Forward air control is the provision of guidance to Close Air Support aircraft intended to ensure that their attack hits the intended target and does not injure friendly troops. This task is carried out by a forward air controller . For NATO forces the qualifications and experience required to be...

 squadron. It was organized on 8 May 1965 under the initial command of Lieutenant Colonel Jack Martin, and was assigned to the 2nd Air Division and attached to the 6250th Tactical Air Support Group (Provisional) at Pleiku Air Base

Pleiku Air Base

Pleiku Air Base is a former air force base in Vietnam. It was established by the South Vietnamese Air Force in 1962 at an undeveloped airstrip, and was used by the United States Air Force during the Vietnam War in the II Corps Tactical Zone of South Vietnam. It was seized by the Vietnam People's...

, but it did not become operational until 1 August 1965. On 8 November 1965, the squadron was reassgined to the 505th Tactical Control Group

505th Command and Control Wing

The United States Air Force's 505th Command and Control Wing is organized under the USAF Warfare Center. The 505th CCW is dedicated to improving warfighter readiness through integrated training, tactics development and testing for operational-level command and control of air, space and cyberspace...

, which was headquartered at Tan Son Nhut Airport near Saigon.