I am a person I can say honestly that is very hesitant around heights. I do not mind so much being on an airplane, or some other enclosed area, because it is as I tell people, I am not afraid of the heights themselves, rather of falling. One of the things that is depicted in comics is generally characters overcoming fears which would leave the best of us frozen or running away, but one of the most interesting problems that characters have to deal with is falling. Of course this applies mostly to non-powered heroes, and in general probably poses a problem either to the residents of Gotham or to their Marvel counterparts (for instance Daredevil) the most often. The most compelling aspect of overcoming this threat is that it is at the expense of logic. A body in freefall will be moving at around 200 kilometers per hour and can be more than double that in a dive, thus the concept of figuring out some way around the this problem is pretty difficult. Generally the solution is to rope something and transfer the downward momentum of the body into something else. Of course this would mean that an extremely durable rope would need to be found but even this leaves something to suspension of disbelief. 200 kilometers per hour is pretty fast, about double what most cars drive on average on a highway, so using only a rope to stop themselves is a bit far fetched. The most recent time I read this was in Catwoman #5 and at least they had the good sense to make it that Selina dislocated her shoulder (though her whip would need to be made out of carbon fiber or some like that.) At least this added a degree of reality to it though, it often times gets portrayed even more ridiculously, such as in Batman and Robin (the movie) where Mr.Freeze is able to stop his fall by creating a snowstorm.