Who's he?
He's a passenger.
Who's she?
She's a flight attendant.
What's he doing?
He's going to his/the gate.
What's this?
It's luggage.
Who's he?
He's the security guard.
What's he doing?
He's going through security.
What are they doing?
They're boarding the plane.
What's he doing?
He's checking in his luggage.
What's he doing?
He's getting his boarding card.
What's she doing?
She's showing her passport-
Who's he?
He's a pilot.