I'm sure that if F9 were to suddenly shut down, UA would be able to put those 24 planes they are grounding right back into the air with very little work. But then again, why would you not just raise your fares? Thereby you are matching the price with the demand and not flooding the market with cheap tickets and lowering overall profit margin. If I were in charge, what I would do would be to help push F9 right off the cliff, and then take the extra seats out so I could benefit twice from their closure. In the current market nobody is going to fund an airline too long, and for proof, look at Skybus.