As the proposed US Airways Inc. merger with American Airlines remains stalled at the federal level, several mayors -- including Philadelphia Mayor Michael Nutter -- have sent a letter to U.S. Attorney General Eric Holder urging that the Justice Department drop its opposition.

The mayors of seven cities have sent a letter to Holder saying that allowing US Airways to join with American would strengthen airports and help even the competition in the airline industry.

Andrew Stober, chief of staff of the Philadelphia Mayor's Office of Transportation and Utilities, said international expansion is vital for the region -- and US Airways doesn't have the aircraft necessary to do the job.

"Philadelphia competes with cities across the region and around the globe and having the connectivity to a global airline network that the American Airlines and USA merger would provide is very important for the region," Stober said.

The mayors of hub cities are urging a settlement in the case that's set to go to trial Nov. 25.

There is precedent, Stober said, citing deals that paved the way for the mergers of Delta and Northwest, as well as United and Continental.

The mayors' letter also noted the merger will keep many people in their jobs and give them the opportunity to work for a financially stable and competitive airline.