AP Theodore Roosevelt became the first president to fly in a powered plane in 1910, after he had left office. In the century since then, the presidential aircraft has evolved into one of the sophisticated planes in the air. The commander-in-chief is more than just an American leader, the office is of global importance. As the "Leader of the Free World," the American president has to be able to travel all over the US and around the world — safely. So of course, the United States Air Force has a special plane for the president. This wasn't always the case, however. What we call "Air Force One" isn't the name of the plane, it's the callsign for any plane the POTUS happens to be on (so yes, if President Joe Biden went Groupon skydiving in a decades-old rust bucket Cessna, that plane would be Air Force One for a brief, shining moment).