I'm not sure what most of the guys who ran that organization flew previously, but all but one or two of them were ex-USN & USAF pilots, and most flew fighters, I believe. The guy I flew with was only one or two who had not previously been a military pilot. I'm ex-USAF myself, so felt right at home there.
The picture above with the SIAT and the O-2 is great, since I flew in both of them. I've never seen a picture like that before. I'll definitely have both of my models displayed together.