I think the only company where job fairs are a waste of time (for civilians at least) are at American. I met them at two (keep in mind this was over 4 years ago). At the first one, I got a "keep up the good work" after waiting 11 hours. At the second one, the recruiter told me that I had too many fighter pilots ahead of me for a job. That's almost verbatim. I was there with many colleagues, some with stellar qualifications, and ZERO got calls from AA.

I remember when I did Emerald Coast interview prep, at least half if not more of my group were fighter pilots, and if I recall, all had an interview with American. The rest of us were still waiting for a call or had a call with UA and DL, or an LCC.

That all being said, I HIGHLY recommend going through ECC prep to get polished before going to a job fair if you can. My first job fair, I hadn't done any formal prep, and I was asked TMAAT questions on the spot and I did NOT have polished answers. I only made that mistake once.

Best of luck.