This is a very interesting news story about a young man who decided to put on his Tefillin to do his morning prayers on an airplane. Apparently the passengers and crew didn't know what they are and got scared.

Before 9/11 I used to put on Tefillin regularly on airplanes. Since then I do everything I can do get my prayers done before boarding the plane or after landing. Once or twice I have had no choice but to put Tefillin on on the plane. What I did was start a conversation with the passengers next to me and explain to them what I was doing and also tell the flight attendant so they would see that I was a normal friendly person and not get scared. It worked fine for me. Apparently this young man just whipped out his Tefillin and strapped them on. 

There is something very interesting in the Shulchan Aruch in the laws of Shabbat. Normally it is forbidden to even handle Tefillin on Shabbat since we have no use for them. The exception is if Gentiles come to attack a Jewish community. In such a case one is allowed to put on their Tefillin on Shabbat. The reasoning is that Gentiles are scared when they see a Jew wearing Tefillin and this will help the Jews defend themselves. Perhaps this young man should have kept that Halacha in mind.