Clay was assigned as vice commander in chief, Pacific Air Forces (PACAF), from February 1970 to September 1970 when he assumed command of Seventh Air Force with headquarters at Tan Son Nhut Air Base, Republic of Vietnam. He also was deputy commander for air operations, Military Assistance Command, Vietnam. As Seventh Air Force commander, he was responsible for all Air Force combat air strike, air support and air defense operations in mainland Southeast Asia. In his MACV capacity he advised on all matters pertaining to effective use of tactical air support and coordinated Vietnamese air force and United States air operations of all units in the MACV area of responsibility. General Clay became commander in chief, Pacific Air Forces, in August 1971.