I went to one in Florida. They did a presentation on the company, spoke a little about their values and future plans. After that the 14 or so guys that were there all got called in for a one on one HR interview. Very quick and nothing very in depth. I got an email that afternoon for an interview in Salt Lake City.
When I did the sim ride out in Salt Lake during the "big" interview the guy told me that they keep the frasca in the trailer so they can take it to job fairs and some local recruiting events for full interviews.
I guess like RickAir said it just depends on which fair and location you will attend. Good Luck!!! My app was in for 3 months without a call and the job fair scored me an interview that gave me a class date. PM me if you want any more specific info.