A US aircraft carrying the President of the United States
Air Force One is the official air traffic control call sign of any United States Air Force aircraft carrying the President of the United States. In common parlance the term refers to those Air Force aircraft … see full wiki
It may carry the most important person in the U.S., however, it causes traffic chaos whenever it goes! Practically all air traffic has to be halted wherever Air Force One chooses to land. I was in Chicago once and President Bush happened to land that very night causing all the delays in flights out of Chicago and missed connections! It seems that the airport will not have any flight taking off or landing in the interval and has to close at least for an hour or so!
Imagine the horror of missing connections for all party concerned!