We were up at Universal CityWalk a couple weeks ago, and we noticed that the indoor skydiving facility which we'd seen advertised on a prior visit had actually been built and was up and running. We stood and watched for a little while, and even that was a lot of fun.
They take you in groups, and presumably, after some kind of talking to, they take you into the glass-enclosed chamber. The rest of the group is waiting just outside the flight chamber while the instructor takes one person at a time, showing them how to position their body and sometimes physically helping them to adjust their body. The communication is done mostly through body language and physical assistance since the mechanism is so loud that you really can't hear much, and both the instructor and machine operator are wearing earplugs, presumably so they don't go deaf on the job. After they go through the entire group, the instructor goes back and asks if anyone wants to go again. It's only about a minute of "flight time" each turn, which doesn't sound like much, but it's actually a good amount of time, given what you're doing.
It seemed to me that control of your movements is similar to that of being on a Segway in that the slightest body part adjustment and position can cause a lot of changes, and "steering" is done completely by body part position.
Some people adjust faster/better than others. Some people were having to be guided and steered the whole time and were bumping into the sides. Some people positioned themselves better so that the instructor had an easier time letting them be blown up and drift back down. One guy we watched did so well that for a little while, he was actually "flying" by himself, without touching the sides and without the instructor having a hand on him at all.
There was also a young boy (maybe 4 or 5 years old) in one of the groups we watched. He seemed to be having a good time, and he even went a second round. At his small size, you apparently have to keep your head up to control yourself better, and they had some difficulty communicating that to him. He ended up flipping a little, but with his light weight, the instructor had no trouble keeping a hold of him. (They all had on special suits which also appeared to have hand-holds in several places.)
I'd heard of this kind of activity before, but I recalled always hearing that they were indoor facilities. Having this be outdoors and totally visible probably made it more fun for the people doing the flying, but it was also fun to be able to watch, and I would expect that the opportunity to see exactly what happens would entice more people to try it.
After everyone in the group was done, the instructor did a little demonstration, repeatedly zipping up to the very top and then diving down really fast, each time stopping just in time. Very impressive.
It looks like a lot of fun, and the husband definitely wants to try it sometime, but it's seriously not my kind of thing, so I'm going to pass and just content myself with watching and probably taking video.