The Douglas VC-54C Skymaster is the first aircraft purpose-built to fly the President of the United States. Carrying the staff transport VC designation, the aircraft was officially named The Flying White House. However, the aircraft became better known by its unofficial nickname, Sacred Cow, a reference to the high security surrounding the aircraft and its special status.

The Sacred Cow carried President Roosevelt to the Yalta Conference in February 1945. Illustrating the high stakes associated with presidential airlift, the Sacred Cows serial number was changed for the flight as a special security measure. The trip to Yalta was Roosevelts only flight aboard the aircraft before his untimely death in April 1945. Roosevelts successor, Harry S. Truman, used the aircraft extensively during the first 27 months of his administration.