This is the only VC-54C built, 42-107451, the first dedicated presidential aircraft. It had the fuselage of a C-54A with the wings of a C-54B for extra fuel capacity. Known as "Sacred Cow' in view of its highly sensitive security profile, for President Roosevelt's only flight aboard it to the Yalta Conference in February 1945, it was marked with false serial 42-72252 belonging to a C-54 which had been lost in the Pacific. Roosevelt's successor, Harry S. Truman signed the 1947 National Security Act aboard, creating the USAF. Retired from regular transport work in 1961, it went to the USAFM 1983