One of the main reasons airlines get propped up is the same reason they are in such financial distress all the time:

UNIONS

Unions absolutely crippled the airline industry. Pilots, Flight attendants, Baggage Handlers, and every other group of employees each have their own union. These unions prevent the airlines from operating like a normal business, and thus, airlines are horribly inefficient and prone to repeated failure.

This same union power is used to lobby congress for help any time an airline is about to go Tango Uniform. If the airline actually closed up shop, it would probably get replaced by a non-union airline. That just won't do!

Unions are a once necessary evil that are now nothing but a leech and a drain on our economy. The internet and the media provide a more effective control on abuse than unions do in modern times. Unions do nothing but cripple business (and in turn, our economy) while at the same time sucking the blood from the worker via dues (which are used, among other things, for political contributions to candidates and causes the workers may not even support).