I don't know if I would call it a phobia per se, but I am not really comfortable with tight spaces. Very slight claustrophobia, perhaps. I don't freak out in elevators or anything of the sort, but the thought of being buried alive under a collapsed building, an avalanche or what have you, is pretty damn scary. I also may have a very slight fear of flying. I don't sweat like a pig and grip the seat with white knuckles all though the flight; in fact if things go smoothly I may be very relaxed, but when there is turbulence my stomach kind of flutters and my heart may skip a beat or two. I guess it ultimately boils down to the feeling that I'm not in control of what happens. Strangely enough I don't have that same fear at all in a car, train or any other form of transportation, even if I'm not the one who is driving.
It's funny cause I didn't have any fear of flying whatsoever till I was in my mid 20s or so. Then I started having recurring nightmares about being in a plane crash, and that got the ball rolling.