When the President is on a civil aircraft, which call sign is used?

The correct call sign used for a civil aircraft when the President is aboard is "Executive One." This call sign specifically designates the aircraft as being used for the President, distinguishing it from other civilian flights.

The term "Executive One" signifies that the President is on board a non-military aircraft, thus aligning with established aviation protocols for such situations. It maintains a clear and formal designation for air traffic control and ensures that appropriate measures can be taken regarding the aircraft’s movement in controlled airspace.

Other terms associated with presidential aircraft, such as "Air Force One," typically refer to military planes specifically assigned for this purpose. Civilian aircraft operated by the President do not utilize "Air Force One" as it is exclusively tied to military transport. The designations "Civilian One" and "Executive One Foxtrot" do not represent recognized call signs in this context, making "Executive One" the correct and accepted terminology for civil aircraft when the President is on board.