Air travel arrangements for the President are made by the White House Military Office and typically one of two customized Boeing 747-200B jetliners are used. These aircraft carry the military designation VC-25A.
The Vice President of the United States, Secretary of State, Secretary of Defense and other high-ranking officials typically use customized Boeing 757-200 and Boeing 737 aircraft which carry the military designation C-32A and C-40B. The President more often uses these aircraft instead of the VC-25A, as the C-32A and C-40B are twinjets that can carry a smaller air crew and use shorter runways, while the VC-25A is a four-engine jet that requires considerably longer runways for takeoff and landings.
The callsign of any aircraft is regular if it is not currently carrying the President or Vice-President. The callsign of any military aircraft that currently carries the President is called that military branch name followed by “One”, such as Army One, Air Force One, Navy One, or Marine One (which is typically associated with a helicopter). The callsign of any military aircraft that currently carries the Vice President is called that military branch name followed by “Two”, such as Air Force Two, Coast Guard Two, or Marine Two (which is typically associated with a helicopter). In the one instance that the President traveled on a private aircraft its callsign was Executive One, and Vice President Rockefeller’s private Gulfstream was Executive Two when he was on board during his term of office.
In addition, the US military maintains a fleet of Boeing C-40 Clippers (Boeing 737-700), C-37As (Gulfstream V) and C-37Bs (Gulfstream G550) for use by government officials, Members of Congress and the White House.