Anyone who has ever flown to or from Israel is familiar with the sight of a minyan of men forming up, usually at the back of the plane, to say whichever prayer co-incides with the flight. Many of those of us who frequent such minyanim will have been shocked by the widely reported news that a Chasid was removed from a flight for praying in his seat as the flight was about to take off. Not getting in anyone's way, not making a noise even - just shockling back and forth in his seat a little.
Now I must admit that I've said a few prayers whilst flying - particularly when we've hit bad turbulence - most flyers would, I think, admit to saying a silent thanks upon landing safely at the far end after a bumpy ride - I certainly won't be in future, knowing it could get me kicked off the plane.
I think that that this could be setting a rather dangerous precedent if people are going to be thrown off a flight every time another passenger reports that a person on the flight is making them nervous. I for example, am made nervous any time I see a young Muslim man on an airplane; knowing that the majority of hijackings have involved this demographic, I think that I this is perfectly rational - so do I report my concerns? If I were to get on a plane wearing a kippa and find myself sitting in front of a crowd of tatooed, National Front supporting skinheads, I'd certainly be nervous but they might equally report a sudden, atypical case of nerves in order to spite me and have me removed from a flight.
Where does it end? The possibilities for madness are fairly clear - it certainly doesn't appear that this guy was doing anything threatening, bothersome or even out of the ordinary - merely sitting in his seat. A simple solution presents itself in order to prevent possible (even likely) abuses of the precedent. You feel nervous about someone without being able to provide a valid reason? Fine. Seeing as the airline's security checks have not turned anything up, we'll be happy to remove you from the flight and you can pay for a new ticket on a flight which you'll be comfortable with. Then we'll see how nervous they really are.