I have a strange fear of heights. On top of a building or suspended by cable on a ski lift or at an amusement park, these give me the willy's and make my feet hurt.
I have no fear of flying in a helocopter with the doors off and the seatbelt loosened so I can sit sideways and shoot photos, a bodyharness is mandatory for me these days though. Spent a lot of time in small a/c both rotary and fixed and was comfortable at all times, but buildings, cliffs, tall ski lifts and amusement park cable cars I pass on nowdays.