Possible Clues:

• Conductor's come-on?
• Get on with it
• *Important American document? (... first 4 letters + the last 3)
• Airline entree?
• Like some public-school pupils needing exam success - a prerequisite for high-flyers?
• Living-in pupil's exam success, needed for high-fliers?
• In residence at college, I don't know what's needed to get through the gate
• *Flying need
• Ticket to fly
• Possibly drop in bags as requirement if you're flying