The custom modifications include interior reconfiguration for presidential duties: sleeping quarters, office areas, two kitchens, a medical operating table and pharmacy[?], communications systems, telephones and television sets, even workout rooms. Operational modifications include in-flight refueling capability and anti-aircraft missile countermeasures.
Air Force One flights are handled as military operations with all flights managed by Air Mobility Command's 89th Airlift Wing at Andrews AFB in Maryland. The President often flies a US Marine Corps helicopter, callsign Marine One, between the Andrews AFB and the White House. Similarly, if the president is travelling on an Army aircraft, it is known as Army One. A civilian plane carrying the President gets the callsign Executive One, and a plane carrying a member of the first family will be called Executive One Foxtrot.
The callsigns were established during the Dwight D. Eisenhower administration.
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