It would probably be pretty easy to see when flights from Egypt land at JFK (assuming there wasn't a connecting flight in London) and then checking on when scheduled flights leave JFK for Montana. How much time was there to proceed through customs? I have a feeling there was plenty of time to make that flight. I also have a feeling that our 5 tardy "students" were helping their buddies, and that is why they "missed" their flight.
I also suspect they may have had help from one of the many Muzzie taxi and limo drivers that service JFK.
My theory is that the FBI counting to 2000 verrry slowly before looking for them. Hey, Guys, it's time to call, "Olly Olly In Free!"
Heh! Heh! Heh! It's been a while since I've played "Hide 'n' Seek". Should have written "Olly olly ox in free!" :o)