Reassigned to Tactical Air Command, re-equipped with new McDonnell F-4C Phantom IIs in 1964. Deployed to bases in Thailand in 1964-1965 flying air superiority missions, close air support, strategic bombing over North Vietnam and initiating "night-owl" tactics and procedures in the fall of 1965 over North and South Vietnam during early stages of the United States' involvement in that conflict. Returned to George Air Force Base and became a replacement training unit for F-4 aircrews from February 1966 to October 1968. The unit became nonoperational for a short time.
