I don’t understand this, really. I’ve flown to NY and Philly and have frequently seen Orthadox Jews praying in the departure lounge, etc. *shrugs*
If he was washing his feet and bowing to Mecca there would be no problem.
There are time limits on when you can start to do this. If your flight leaves too early in the morning you can’t put on tefillin in the airport (besides, there is more privacy in your seat in the airplane). When I have done this I have notified the flight attendant so she can see what I’m doing.
There was a train in Chicago about a year ago that was halted because someone was putting on tefillin, he was sitting next to a sikh in a turban, and nobody knew whether they were together and what they were doing.