It is however possible that if you post something which is reasonably libelous someone might go to the trouble of suing. It's also remotely possible that an airline might sue even on marginal grounds strictly to justify a subpoena to identify someone (so they could discipline/fire him). A certain bottom-feeder regional is widely reputed to have done exactly the latter.
Say what you want to say, just be smart about the manner in which you say...if it's adverse info, don't state that it is fact unless you know and can prove it's fact. You should still be entitled to your personal opinion as long as it is clearly just your opinion.
Previous discussion here...
http://www.airlinepilotforums.com/ha...-internet.html