NEW YORK (CNN/Money) - Management at financially troubled United Airlines remains in a holding pattern while the airline's unions try to negotiate a cost-cutting labor agreement between themselves.

The coalition of the airlines' union has already missed its own Sept. 19 target date. Representatives of the unions met with each other through the weekend and with company management Monday. T.J. Sesko, a spokesperson for the Association of Flight Attendants, told CNN an agreement is expected to be completed by Tuesday night.

"We're trying to make sense of all the numbers and come up with a proposal that makes sense and stabilizes the company, restructuring it outside of court," said Steve Derebey, a United 767 captain based in Chicago and spokesman for the Air Line Pilots Association.

The airline has warned that it will be forced to seek bankruptcy court protections without significant cost savings from the unions along with approval of federal loan guarantees. Jack Creighton, the previous CEO of United parent company UAL Corp. (UAL: down $0.15 to $2.34, Research, Estimates), had set a mid-September target date for such agreements, but Glenn Tilton, who was named CEO on Sept. 2, seems willing to wait to see what the unions produce.

"They're saying they expect to get back to us fairly soon. I think we still have some time," said company spokesman Joe Hopkins. "The deadlines have all been self-imposed. It's not the end of the game."

Analysts expressed doubts whether the unions will be able to reach an internal agreement, let alone come up with the $1.5 billion savings the company says it needs in labor cost savings.

"I would be extremely surprised if what the unions came up with was enough to keep United out of bankruptcy," said Jim Corridore, the airline equity analyst at Standard & Poor's. "Typically these unions have a lot of animosity with each other. I don't hold out a lot of hope."

Related stories UAL seeks $1.5B from labor UAL taps oil exec as CEO UAL flying towards bankruptcy

Corridore points out that while management had previously reached a tentative deal with pilots and some smaller unions and was making progress with flight attendants, it had yet to win any concessions from the International Association of Machinists, the largest union with a majority of ground employees. He said the internal negotiations basically excluding management are unprecedented, not only at employee-owned United but in any labor relations with which he is familiar.

"Labor is taking control of the plane, flying the entire company, and management is sitting there waiting," said Corridore, who has had a sell recommendation on UAL stock since the end of August. He does not own any UAL stock, nor does S&P.

Corridore said even if there is an agreement between the unions, there will be trouble if it does not meet management's demand.

"I think that management is going to look at it as a starting point for further talks, while union sees it as the be-all and end-all," he said. "I would put the chances of staying out of bankruptcy as very thin."