DC-6B XV-FCK was operated by the 314th Special Mission Squadron out of Tan Son Nhut in a role similar to the USAF's Air Force one. Douglas DC-6B construction number 44111 was the 430th DC-6 built. It had previously flown with Pan Am, Avensa, Miami Aviation Corp., after which it was purchased by Air Carrier Service Corporation. They refurbished the plane and it's interior and it was delivered to the VNAF in June 1966. (information taken from: Via Air Mail, article by Terry Love)
Another photo of Air Force One (Photo: Peter Bird)
Apparently this aircraft escaped to Clark AFB, the Phillipines, where the two photographs below were taken by Daniel Capal in January 1982. Why the plane was demolished is not known.