Your specific singular focus might blind you to all the other reasons planes have been hijacked: https://en.wikipedia.org/wiki/List_of_aircraft_hijackings

and potential incidental dangers from unrest in confined spaces.

@defrost: I apparently can't respond directly to you. It's a mistake to ascribe a singular focus to someone you don't know. There may be one out of ten thousand people in any group who might want to cause chaos or violence, and they may very well have their own reasons. It would be absurd, though, to not acknowledge that there are some "gospels", if you will take that term in the broadest sense possible, or sub-religions, which preach that violence is a path to salvation, and which tend to recruit people for the purpose of violence. There are also some political movements which fill the same vacuum for an aimless, angry human soul without religion.

It is not that I have a singular focus on one religion nor one political movement, so much as that the evidence suggests that, currently, some movements have more violent offshoots and a more violent profile. There are a handful of political and religious ideologies in the world that lead to more suicide bombings and hijackings per year than, say, the total number done by believers in Zoroastrianism, Sikhs, Confucians, Hindus, Yazidis, Jews, Buddhists, Libertarians, Democratic Socialists, Freemasons and Christians combined.

If you had, for instance, Jim Jones's cult or the Aum Shinrikyo boarding airplanes and blowing them up on a regular basis, and your response was that a person had to be a single-minded bigot to notice the fact that most airplane bombings originated with this particular ideology, then I'd say you were ignoring facts or willfully making excuses for ideologies which brainwashed people into doing those things. Possibly for reasons related to disliking your own society, which is perfectly fair, but certainly not neutral or scientific.