All kinds of fake papers floating around. Visas, maybe passports.
So, papers don't mean shit, but $6500K up front does. It would most likely stop people from bringing their local national house staff, as well for example, so the seats could be occupied by Americans or NATO civilians.
$6500K may be the best way to vet who he's airlifting out. He can always refund or rebate that.
If he gives the rides for free there's no easy, reliable or quick way he can vet who's on board.
My guess, anyway. IOW, might be one of those things where the rest of the story makes more sense.