CHICAGO (AP) — A merged American Airlines and US Airways will carry more passengers around the world than any other, but even the biggest airline flying doesn't need eight hub airports on the ground.

That means amid the hoopla of Thursday's merger announcement, there are a few mayors, a handful of chambers of commerce leaders and lots of frequent flyers worried about what's to come. Expect their sales pitches to start soon about why their city should remain a hub.

"Nobody has that many hubs," said Robert Poole, an aviation expert and director of transportation policy at the Reason Foundation. "Eight hubs for the merged American would just not be sustainable — too complex and not really meeting enough of the travel needs."