FDR held the key position in a wartime coalition of 26 countries he called the "United Nations." He, Joseph Stalin, and Winston Churchill comprised the "Big Three" at the heart of this coalition. But, as the war progressed, FDR increasingly acted as the group's ultimate broker and decision-maker.
During the war, Roosevelt attended 12 major diplomatic conferences in North America, Europe, Africa, and the Middle East. The Allied strategies that won World War II were forged at these meetings. The most important conferences were the final two - held at Teheran and Yalta. There the Big Three discussed war issues, but they also tangled over the shape of the postwar world.
FDR traveled extensively during the war. Not content to monitor industrial and military progress from Washington, he made extensive inspection trips to factories, testing grounds, and bases.
Roosevelt also undertook overseas trips to attend conferences and confer with military leaders. Some involved weeks of grueling travel by sea, land, and air. FDR preferred journeying overseas by navy ship. These were outfitted with elevators and railings to accommodate his disability. In 1943, he became the first sitting president to fly when he traveled to the Casablanca Conference aboard a commercial aircraft. Military concerns later led to construction of the first Presidential aircraft - a Douglas VC-54C nicknamed the Sacred Cow. FDR used it to fly to the Yalta Conference. The plane's unpressurized cabin made long distance travel uncomfortable, but it included features that enhanced FDR's mobility, including an elevator that lifted him in his wheelchair directly into the aircraft.