It Can Be Refueled In Mid-Air
Amazingly, Air Force One has the ability to never need to land. It can be refueled mid-flight for security reasons, so the president never has to land in an unsafe situation.
If necessary, the plane could fly forever, or at least until there was some kind of serious mechanical failure. But even then, with a plane like this, who knows? On top of mid-air refueling, Air Force One has a gas tank that can hold 53,611 gallons. That should last you for a while!