Up until World War II, the president of the United States rarely traveled far from home. Visiting other countries simply took too long, and it cut the president off from the major institutions of government.
The rise of air travel made it feasible for the president to move around the globe and return home in short order. In 1943, Franklin Roosevelt became the first acting president to take to the air when he rode a Boeing 314 "flying boat" to a wartime conference in Casablanca.
Roosevelt took the plane because German U-Boats made the seas too treacherous, but the success of the mission established air travel as the standard mode of presidential transportation. Soon, the government decided to assign a military aircraft for presidential use. The Air Force originally selected a C-87A Liberator Express, basically a B-24 bomber configured for civilian operation, which was christened the "Guess Where To."
After another C-87A crashed under mysterious circumstances, the Secret Service decided it wasn't a safe plane for the president. They soon configured a C-54 Skymaster for Roosevelt, complete with sleeping quarters, a radio telephone and a retractable elevator for Roosevelt's wheelchair. The plane, nicknamed the "Sacred Cow," carried Roosevelt on several important missions, including the historic Yalta Conference.
President Truman took over the Sacred Cow, and later replaced it with a modified DC-6, which he dubbed the "Independence." Unlike the Sacred Cow, the Independence was covered in patriotic decoration, including an eagle head painted on its nose. President Eisenhower introduced two similar propeller planes, with upgraded equipment, including an air-to-ground telephone and an air-to-ground teletype machine.
In 1958, presidential travel took a giant leap forward when the Air Force introduced two Boeing 707 jets into the fleet. The Air Force began using the radio call designation "Air Force One" during Eisenhower's administration, and the public took it up after Kennedy took office.
At the beginning of his term, Kennedy added a more advanced, long-range 707, and oversaw an aesthetic redesign -- the blue and white decoration still used today.