First of all, I'd be cautious about talking about it on a public forum until it's settled. It sucks, but like Derg says, the interwebz ain't so anonymous.
It sounds like you're doing the right thing by getting an attorney. I would still apply to airlines, and not bring up the arrest in an interview unless you are convicted. It is illegal for an interviewer to ask if you've been arrested. They can (and do) ask about convictions, however. If the conviction is coming down, and you know it, it would be prudent to let them know about that fact beforehand. Otherwise, innocent until convicted, in my opinion.
Try like hell to get it reduced, but I don't think it will be a deal breaker necessarily. Unfortunately you don't have the benefit of time-since-event in your favor. If it comes up during the interview, focus on what you've learned from it, not how you were "screwed by the man."