It is completely understandable that the kid couldn’t have imagined a problem with doing this.  There are air routes where this occurs regularly , certainly on flights to and from Israel but also on many others into and out of cities with large Jewish populations.   He may have flown on one of those routes in the past; or he may have heard people in his community talking about praying on planes (there is extensive halachic literature on whether and when it is permissible and how to do it properly); or he may even have asked his rabbi before the flight what he should do if he couldn’t say his morning prayers before flying, and his rabbi (who also couldn’t imagine that there would be a problem) told him pray on the plane.  It is not at all surprising that he didn’t see anything wrong with doing so.  The people who are blaming him for what happened are just being idiots, most of whom are probably motivated by anti-Semitism or generalized anti-religious bigotry.

On the other hand, the people who are criticizing the flight crew for overreacting are also being unreasonable.  Is it really so unbelievable that a flight attendants on a plane bound for Kentucky would not be familiar with tefillin?  There are people in this country who have never met a Jew, let alone one who wears tefillin every day.  There are people who actually believe that Jews have little horns. You can mock that all you want, but when somebody stands up in mid-flight and starts strapping things to his head and arm, and when the flight attendant asks what he’s doing, he responds tersely because he’s in the middle of praying and not supposed to talk, exactly what is s/he supposed to think?

The people who have asked why no one else on the flight stepped in and explained to the attendants what was going on, have clearly not thought things through very well.  First of all, there were only 15 passengers on the flight.  Again, on a flight bound for Kentucky, just how many of those fifteen passengers do you think were familiar enough with tefillin to explain them coherently?  Independent of that, when there is an in-flight security situation, the crew does not advertise that fact to the passengers, nor do they even tell the passengers they are diverting the plane until it is absolutely necessary.  If the crew handled the situation properly, no one knew what was going on until long after the decision to divert had already been made.

This was an unfortunate incident in which reasonable actions by everyone involved led to a seemingly unreasonable outcome.  That happens sometimes, and vilifying people over it is just silly.