This job fair is actually just an outgrowth of JetCareers' annual forum meet-and-greet, which in itself has previously yielded a lot of great job opportunities through networking informally. Even if the companies represented don't float your boat in terms of employment opportunities, maybe meeting some of the people in attendance will.
Either way, why not just go join the forums at JetCareers and start participating even if you don't go to the job fair?