Air Force One was the official plane for the President of the United States. It was used when making official trips around the world.
During the 2012 Apocalypse, Air Force One was used by several U.S government officials (ironically, minus the President himself as he chooses to stay behind with his wife and his people but his daughter didn't stay behind) to fly from Washington D.C. to China when the worldwide apocalypse happened. They luckily avoided the ash cloud that engulfed the United States just a few hours before it. Inside, many government officials collected updates on information regarding the apocalypse, recording seismic and volcanic activity, which caused earthquakes, volcanic eruptions, and tsunamis that destroyed the Earth's continents and killed billions globally.
Air Force One later landed at Cho Ming Airfield in Tibet alongside other planes to reach the Arks. The plane was later swept by a mega-tsunami when the Worldwide Flooding occurred. Just after the mega-tsunami struck the Arks, Air Force One was destroyed when the plane collided into Ark 4.