Air Force One is a highly customized military version of the Boeing 747 airliner, specifically a Boeing 747-200B model designated as the VC-25A. There are two of these aircraft in service, with tail numbers 28000 and 29000. These planes are equipped with advanced communications, security systems, and can refuel mid-air, enabling the U.S. president's worldwide travel with extensive onboard facilities and protections. Newer models based on the Boeing 747-8I, designated VC-25B, have been ordered to replace the aging VC-25As but are expected to enter service around 2027.