I wouldn't really call that "Saving" Frontier... AA would get a couple of new planes and routes, but everything that made F9 special would likely be roadkill in that merger scenario.

What about JetBlue? Despite their fiasco last year, I haven't heard any stories about them having problems due to fuel... are they fairly sound? B6 seems the closest to F9 in terms of philosophy, good crews, and similar equipment (though I hear they use different engines on their Airbii which could be a problem), and they don't have much route structure overlap. Every time I get on B6 I am surprised at how similar they feel to Frontier... if anyone is going to buy up my favorite carrier, I hope it's them.