Two months after the death of President Roosevelt, and with W.W. II almost at an end, the censorship concerning FDR's presidential aircraft was terminated. The reporters at Newsweek were not slow in reporting all that could be known about this comfy juggernaut that had spirited FDR to Malta, Yalta and Cairo. The plane, titled Sacred Cow, was a Douglas C-54A, reconfigured to sleep five and was equipped with an inter-cabin telephone, radio, an electric toaster, and a stateroom. The President had anticipated traveling hither and yon while planning the post-war world, but other plans got in the way.
Recognizing that the name Sacred Cow lacked the necessary solemnity that would be appropriate for the office of the presidency, the name of the chief executive's private plane was eventually changed to Air Force One.
More about FDR's aircraft can be read on this website.
More about FDR can be read here.
More about aviation can be read here.
