Since man invented the ship, car, train and plane, there have been no new inventions in the field. The World has remained stagnant. The energies available have been expended on already existing modes of transport. It amounts to a misuse of resources.
While it sounds innovative, it is based on the belief that one will only see "good" things out there. I doubt that it would be a good idea to make a transparent glass plane even if strong enough material were to be found. The fear of heights for example only comes upon the realization that one is so high up from the ground. If unaware, a person can function "normally", hence people on cliff being told not to look down.
Claustrophobia.... It kills so easily. Just ask the police who lock up perfectly healthy people in the cells and return to find them dead
You are right. This is not for the faint hearted. One can easily think he is falling off the skies. So scary.