I'll speak from my experience, which is almost 15 years old. OAF (aka "Ops") is a summer program for AFROTC and USAFA cadets that takes place at AD USAF bases. It used to be three weeks long. When I went, it was the summer after Junior year for AFROTC people, and it was not mandatory (at least for college program people like myself). I think it's one of the mandatory things USAFA cadets do in the summer, and I had a few of them with me at my assignment (I think they went the summer after soph. year). It was three weeks at a base, and we chose two AFSCs to "shadow" for a week. The first week was a general intro to the base/surrounding area, the second week I went with the Intel people, and the third week I was with an aircraft maintenance squadron. There are also incentive rides in aircraft (if available), and you do things like go to the CGO Association meeting to get a feel of what it'll be like on active duty. It's sort of like playing "3rd Lieutenant," as you follow a junior officer around during the day and then you have the nights to hang out with the other ROTC/USAFA cadets. Sometimes you might do some training ops at night, but mostly the evenings are your own time. An AD officer from the base is the sponsor for the training, and you stay in Billeting.
I was lucky that my OAF was at Hurlburt Field, in Destin, Florida. I flew on an MH-53 Pave Low, an AC-130 Spectre gunship, and got to hang out at the pristine beaches in the area. It was a good time socially and professionally. Once I went on AD, I became a missileer at Minot (which is @ the other end of the spectrum
). Interestingly, when I was a LT, I'd see the USAFA/ROTC guys @ Minot for their OAF. I always wondered who they ticked-off. They seemed to enjoy the tour of our facilities, though.
A good program. I'm sure it'll be offered for ROTC guys at some point again.