The 20th Helicopter Squadron was formed at Eglin AFB, Florida in November 1965 under the command of Lt. Col Lawrence Cummings. Training was provided by the 4401st Helicopter Squadron, under the "PONY EXPRESS" Project. The pilots selected were the most experienced CH-3B/C pilots in the Air Force at the time since the CH-3B/C had been operational with the USAF for a very short period of time.
After a month of training and checkout, the Squadron was deployed to South Vietnam in November 1965. The Squadron initially was stationed at Tan Son Nhut Air Base near Saigon. The CH-3C helicopters, which had been disassembled and flown to Viet Nam in C-133 aircraft, were then assembled and readied for duty. The Squadron was split into three flights; one stayed at Tan Son Nhut under the command of Major Richard Burdett. Another flight was sent to Danang Air Base under the command of Major Herbert Zehnder with six CH-3C aircraft. The third flight was assigned to Cam Ranh Bay.