If it doesn't, there's no apparent agitator-in-waiting either to lead a creditor protest or propose a plan. Ditto when it comes to an alternate acquisition proposal.

"I don't think the financial community is knocking down the door to buy a bankrupt airline," Perkins said, adding that, just as unlikely, is the emergence of a competing plan from any other involved group. "It would be a pretty cowboy move at this point."

So with all its eggs in the basket of a marriage to US Air, AMR's bankruptcy strategy going forward will rely on winning the DOJ lawsuit. It's a dicey gambit, since neither AMR or US Air has seemingly offered any concessions regarding its flights out of Reagan National Airport in Washington, D.C.

David Braun, a partner at Quarles & Brady who has worked in the DOJ's antitrust division, points to the Reagan situation, where US Air holds 55% of the slots. That figure would increase to 69% for the combined company with the merger.

Braun said the Reagan slot issue is a "very important part of the picture because of the importance of that airport to both carriers. The fact that the lawsuit was filed shows that there was a failure of US Airways and American to find a resolution, what we used to call a 'fix-it-first' solution to the merger. That would usually entail giving up slots at some of the few airports where there is control over capacity."

Annamarie A. Daley, administrator of Barnes & Thornburg's antitrust and competition law group, said those slot issues are likely to attract even more attention because of their location in the nation's capital.

"This is going to be something that Congress is going to be paying close attention to because of Reagan, where members of Congress are frequent fliers," she noted. "They'd be direct observers of any impact of reduction of competition from the merger. It's a classic supply-and-demand analysis and any increase in prices will hurt consumers."

Quarles' Braun asserted that giving up slots at Reagan probably isn't enough on its own to complete the merger, but would be "a crucial step in finding a resolution."

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