DALLAS — US Airways CEO Doug Parker has landed the big merger he sought for years. Now the soon-to-be CEO of the new American Airlines has to make it work.

Planes need painting. Frequent flier programs have to be combined. And the new airline will still be weak in Asia and need to win back business travelers who have been drifting away to other airlines.

The two airlines announced an $11 billion merger Thursday that will turn American into the world’s biggest airline, with some 6,700 daily flights and annual revenue of roughly $40 billion. It’s a coup for Parker, who runs the much-smaller US Airways and has long pursued a deal like this one with the strong belief that airlines would have a better shot at consistent profits if they bulk up through mergers.

The latest deal will mean that the four biggest U.S. airlines are all the product of mergers that began in 2008. Those deals bring benefits, but they also show that putting together two airlines smoothly is not easy.

Some of the work on the latest combination has already been done. Pilots from both airlines have agreed to the outlines of a deal that should make it much easier to get a final, joint contract. And Parker is inclined to use American’s computer systems such as those that track reservations and passenger information, he said on a conference call. He said past mergers have shown that it’s easier to use the bigger airline’s technology, because then fewer people at the smaller airline need to learn it.

Noting those factors, JP Morgan analyst Jamie Baker predicted a “relatively smooth” transition.

The combined carrier is going to be called American Airlines and be based in Fort Worth. The deal is expected to close by the end of September, as part of American’s emergence from Chapter 11 protection.

Even after that, travelers on American and US Airways won’t notice immediate changes. It likely will be months before the frequent-flier programs are combined and years before the two airlines are fully integrated.

Most airline mergers have resulted in a reduction of flights and shrinkage at some hubs, but Parker said this deal will be different because US Airways and American overlap on just 12 routes.

He said the new airline will keep all of American’s hubs – Dallas-Fort Worth, Chicago, Miami, New York and Los Angeles – and those of US Airways, in Phoenix, Charlotte and Philadelphia. Many airline mergers have resulted in some hubs being downgraded, as happened to Cincinnati after Delta bought Northwest.

“Hopefully the service will be better with two airlines united to do what one hasn’t successfully done so far,” said Mary Gorman, 63, who was at Miami International Airport on Thursday for a flight home to Virginia Beach after a cruise with her husband. “If the service is better, I don’t mind paying more for a ticket.”

The airlines said they expect $1.05 billion in combined benefits from the merger. They expect the bigger airline to lure corporate travelers away from competitors, contributing to $900 million in additional revenue. They also anticipate cost savings of roughly $150 million.

$400 million in raises

The savings would have been higher, but the company expects to pay out $400 million per year in raises for workers. Unionized workers at both airlines have seen their pay languish, with some US Airways pilots still flying under a contract signed when that carrier was in bankruptcy protection in 2005.

The combined airline also expects to spend $1.2 billion on one-time transition costs over the next three years.

It will stay in the “oneworld” airline alliance, where it is partners with British Airways and other overseas airlines. Those alliances make it easier for international travelers to plan trips that include multiple airlines.

Business travel benefit

The new American would have more than 900 planes and about 95,000 employees, not counting regional affiliates. It will be slightly bigger than United Airlines by passenger traffic, not counting regional affiliate airlines.

Delta and United’s size have allowed them to get more than their share of business travelers, US Airways President Scott Kirby said on a conference call.

For instance, Delta’s shuttle service up and down the East Coast competes against a similar offering by US Airways. But Delta passengers can connect to more overseas cities than US Airways passengers can, and American doesn’t have a shuttle at all. But with the US Airways shuttle feeding passengers into American’s overseas flights, the merged airline would get more business travelers, US Airways argued in its presentation to creditors in January, which was filed publicly on Thursday.

The combination will also boost American’s service to Europe and Latin America and the Caribbean. But some analysts noted that the new American will still be weak on routes to Asia.

“Without a major Pacific presence (just a mere five destinations and eight routes), American doesn’t come close to either Delta or United’s presence in the market,” Helane Becker, airlines analyst for Dahlman Rose & Co., wrote Thursday in a note to clients.