Do you get motion sickness?
I am a nervous person, but tend to hide it well. But when it comes to traveling, I'm as nervous as you can be without having a heart attack (so I just get nauseous instead! yay).
I also get motion sickness on the train and in cars. It seemed to develop over the year, because I used to have no trouble with it. Now that I take the train everyday to school and drive, I have it. Awesome.