I'm thinking that RJET might be the better choice. It's had quite a run-up over the past 6 months, but their management team is ruthless, competent, ambitious, and have cash in the bank.
I wouldn't expect an 800% return in 6 months a-la MESA, but I wouldn't have to worry about losing all of my investment with an overnight bankruptcy filing either.
Like you said . . . buying airline stocks isn't for the timid. I suppose I am, but I've been sitting on the sidelines watching airline stocks for years and I think there's some real money to be made. Just don't bet the farm.