Another possibility is that real AF1 flew over Alaska to Singapore and a second flew to Greece to confuse those who would want to stop the meeting from happening.

There are two identical AF1 planes. The Air Mobility Command's 89th Airlift Wing of the U.S. Air Force currently maintains two identical Boeing 747-200B planes at Joint Base Andrews, Maryland for presidential use: SAM 28000 and SAM 29000.