Air Force Two passengers, in brief

VPS

They’re the ones who step in if the president can’t, often flying just behind Air Force One.

"Air Force Two passengers, in brief" refers to who typically flies on the backup presidential aircraft. The answer is "VPS," short for Vice Presidents—since the Vice President of the United States is the primary passenger on Air Force Two. The clue uses "in brief" to signal the abbreviation, and "Air Force Two" is a well-known term for the VP’s official plane.