Regarding the recent "Question of the Week" on acrophobia: It's often been said that "fear of heights" is really the distress that arises from the conflict between a very strong subconscious desire to fly, while at the same time being in a place (e.g., an apartment balcony, a cliff) where attempting such flight (with a certainty of failure) would be easy. So fear of heights is the result of the conflict between the desires to fly and to survive.
Len Deighton, an author and pilot, mentioned this theory many years ago. And there is some (although conflicting) evidence Lindbergh experienced such a fear, at least in early years. As for me, I'm very happy flying airplanes, low or high, and even with the door off for taking photos but no use at all on the roof of a two-story house.
I've flown jets at 45,000'. I fly helicopters with no doors, looking straight down at the ground. I've been upside-down in open cockpits. No problems with heights there, but the third rung of a ladder will make my knees weak!
As a pilot with over 24,000 hours in airplanes and helicopters, I have to say I do get a chill near a cliff or looking out a window in a tall building! I guess I don't think about it in flight, but when I was flying helicopters in Alaska, I experienced "open sky vertigo" where my altitude went from 100 feet to 3,000 feet as I flew over a cliff into open air. It was a strange sensation, and I have had it occasionally in airplanes. A really interesting question!
Heights in an aircraft do not bother me because there is seldom a true sensation of height. For a true sensation of height, something visual has to connect the observer to the ground below. Hence, a view over the side of a cliff or a building showing a direct connection to the ground (without correcting the "errors of the eye") can be scary.
The appearance of clouds (usually several layers with spacing between and betwixt them) can be thrilling when viewing the ground below and can at times create the scary 3D effect.
I feel safer the higher I am, because altitude gives me more options and more time to resolve situations. My reaction times and cognitive abilities diminish above 10,000 feet MSL or so, but, in general, the higher, the safer for this old buzzard.
I'm a 3,000-hour instrument-rated private pilot. Heights terrify me! I'd rather dodge thunderstorms than do a stall!
A smart instructor figured out that my terror in doing stalls is due to my fear of heights. During the stall, my frame of reference changes from the floor of the cabin to the earth and yikes!
I like the idea of electronic envelope protection. However, as I recall the first successful customer Cirrus BRS deployment was the result of in-flight loss of an aileron (due to faulty maintenance). I wonder how Diamond Aircraft CEO Christian Dries's electronic parachute would have handled that emergency without functional flight controls?
With all due respect to the FAA, I cannot imagine how they could possibly forecast the amount of GA activity out into the 2020s. I can make my own forecast of GA activity in 2012: Without some resolution to the cost of fuel, there won't be any. C'mon, Swift fuel!