Takeoff and Landing
During a takeoff or landing, air traffic controllers give AFO top priority. When the AFO departs or returns to the ground, it is standard procedure for traffic control to halt all commercial traffic at public airports.
Source: Imgur
For obvious reasons, the Presidential plane normally lands at military airports, both for security concerns and to avoid commotion at civilian airports. When the plane does make a landing, the airport is notified far in advance, and the entire airspace is cleared to ensure a safe landing.