“The presidential air transport fleet consists of two specially configured Boeing 747-200B's -- tail numbers 28000 and 29000 -- with the Air Force designation VC-25. When the president is aboard either aircraft, or any Air Force aircraft, the radio call sign is "Air Force One."”
https://thedonald.win/p/11QlKRXrtc/new-af1-tail-number-90017/
“The presidential air transport fleet consists of two specially configured Boeing 747-200B's -- tail numbers 28000 and 29000 -- with the Air Force designation VC-25. When the president is aboard either aircraft, or any Air Force aircraft, the radio call sign is "Air Force One."”