US Airways can accept rival bids to its proposed merger with America West this month, opening a 30-day window for other potential partners to step forward before the pair can talk exclusively among themselves.

US Airways lawyer Brian Leitch called yesterday's ruling by U.S. Bankruptcy Court Judge Stephen Mitchell an opportunity for the Arlington, Va.-based carrier to "shake the tree" and look for higher and better offers.

But while he would not be surprised to see other bidders emerge, America West Chief Executive Officer Doug Parker said in a telephone interview that he expects the merger with US Airways will go forward.

No one else is likely to come up with an offer as comprehensive as his airline's bid for US Airways over the course of the next 30 days, Parker said.

The $1.5 billion merger agreement between the nation's seventh- and eighth-largest airlines involves at least a half-dozen different financing players in addition to the two companies.

If others step forward, Mitchell, the judge overseeing the US Airways bankruptcy, would determine which offer is best for creditors.

If no one does, then US Airways and America West will be free to complete their union, creating the nation's sixth-largest airline with more than $10 billion in revenue and a route network stretching across the country.

In a related merger ruling yesterday, Mitchell approved a $15 million break-up fee that could be paid to either airline if the merger falls apart. But he has yet to rule on the airline's request to have until Oct. 31 to emerge from Chapter 11.

On another front, Mitchell yesterday heard arguments for and against a company proposal to set aside as much as $55 million for the retention of key officers and salaried workers as the US Airways-America West merger works its way through the various regulatory approvals.

The company has modified that original proposal by an unspecified amount.

The introduction of new severance agreements and retention incentives for 1,900 of the company's 25,000 workers has angered union members.

The flights attendants called the idea "preposterous and inequitable," while the machinists union called it a "disrespectful betrayal" of the company's union-represented employees, who gave up more than $1 billion in annual concessions recently.

The pilots union called the retention initiative the "wrong program providing the wrong people with the wrong benefits at the wrong time."

The company defended the policy in court yesterday, arguing that it needs the incentives to hold onto top managerial talent.

Such packages historically have been used by companies in bankruptcy to keep key personnel, and the airline has complained that several managers have abandoned the carrier in the past year amid its ongoing struggles.