The VC-25 is most famous for its role as Air Force One, the call sign of any U.S. Air Force aircraft carrying the President of the United States. The two aircraft currently in U.S. service are highly modified versions of Boeing's 747-200B, with tail numbers 28000 and 29000.
The Boeing C-32 is a military passenger transport of the United States Air Force, providing transportation for United States leaders to locations around the world. The primary users are the Vice President of the United States (using the distinctive call sign "Air Force Two"), the First Lady, and the Secretary of State. On rare occasions, other members of the U.S. Cabinet and Congressional leaders have been authorized to fly aboard the C-32 for various missions. The C-32, since its debut, has also served as Air Force One in place of the larger VC-25A to airports that cannot accommodate the Boeing 747-based "jumbo" jet