They would lose. Hugely.
Airtran would suffer for a bit, actually. Airtran would not be able to keep up with the resultant demand for services, and, as a result, would piss off millions of ATL
bound travellers who wouldn't shake off the initial distaste.
Almost all major domestic carriers would need to add in widebody service in the short-term to carry all the stranded passengers, but, with DL
's 600 flights a day gone and the skyrocketing fares, demand for travel would wane in the ensuing months.
In order for another carrier to pick it up and run with it, they'd need to have a huge fleet in the desert already waiting for reactivation and be able to assemble that in a few weeks. I suppose Northwest could pack up MEM
and move it there, but again, the effort is huge and timeconsuming and the consumers will lose interest rapidly.