TOGALOCK

I don't entirely disagree, but I do think that's pretty broad "one size fits all" advice. In my opinion, a lot depends on the OP's personal situation.

The "millions of dollars more" would primarily be a function of both a good number of years as a widebody captain and profit sharing. Profit sharing in any large quantity will likely not be seen for a long time, and depending on the OP's age, they need to determine how many years they'd likely spend in the left seat of a widebody. They also need to ask themselves, at what point would they transition to a widebody captain spot? At the first available opportunity, or sit on narrowbody captain pay for a good number of years until they could hold a line? Are they even young enough to ever be able to have a chance to make that decision?

Also, we're not out of the covid woods yet and business and international travel is still severely depressed. It's looking more and more like international travel may not recover for a very long time. If covid doesn't shake itself out in the next year or so, I don't think that some furloughs at the big 3 could possibly be out of the question. Of course that could apply anywhere, but considering the domestic demand, I would feel far more comfortable at the bottom of the list at someplace like F9, NK, B6, WN, etc.

It all comes down to life situation and adversity to risk for the OP. If they are young, unmarried/married without kids, and okay with rolling the dice on the possibility of being a furlough casualty then I would definitely say to go for United. If they have a few more gray hairs on their head and will likely never be a widebody captain for a good number of years (if ever), have kids and financial responsibilities at home, and want something slightly less risky then I'd say go for Frontier (the driving to work part is huge).

It's all about personal situation, not an all encompassing answer.