Many years ago, when Eastern and Pan American went under, it was apparent that the majors were in trouble.
There is a reason that Southwest has always made money. That reason is, MANAGEMENT, and if management takes credit for making money, then management takes credit for losing money. It is managements JOB to manage their unions. Southwest does very well and they have employees making less than those of the major carriers, they haul people, make money, if a route is a loser, away it goes.