The Secret Service subsequently reconfigured a Douglas C-54 Skymaster for presidential transport duty . The VC-54C aircraft , nicknamed the '' Sacred Cow '' , included a sleeping area , radio telephone , and retractable elevator to lift Roosevelt in his wheelchair . As modified , the VC-54C was used by President Roosevelt only once before his death , on his trip to the Yalta Conference in February 1945
Yalta Conference
Yalta Conference
Air Force One