They'd have to have signed on as some sort of auxiliary to their local PD or Sherrif's Dept.
Of course, they have to transport their weapon in its baby gun safe from the airport to the home gun safe & back (unless there's a convenient Janitor's Closet near the gate

). Depending on state law, they may need a concealed-carry permit for that transport.
Somehow, the FFDO program seems to have been invented by the same people who thought up TSA ( the airport wannabees, not Trans States!). Not much wrong w/ it; just an ineffective attempt at doing something. Has an FFDO
ever used their weapon for its purpose, rather than just having an occasional accident requiring duct tape and an entry on the MEL list?