I’m blogging all weekend from the Society of American Business Editors and Writers’ annual conference in Dallas.

11:50 a.m. NOW: The chief executive officers of American Airlines and Southwest Airlines sparred over add-on fees and expressed concerns with Boeing’s 787 delays and the manufacturer’s desire to build larger airplanes.

Gary Kelly, the chief at Dallas-based Southwest, which saw record revenue in 2010, said he has no plans to change his company’s policy that checked bags fly free. He added that Southwest was “different” than American CEO Gerard Arpey’s company, and Arpey agreed.

“Philosophically, we’re on a different path,” Arpey said, referring to the add-on fees that Fort Worth, Texas-based American charges for checked bags. “We don’t charge others to subsidize those who want to check bags.” Kelly, meanwhile, noted that his company is charging for other value-added services, such as the wireless Internet that’s available in some of its planes.

American was the only legacy airline to avoid bankruptcy, while Southwest has lately been the most successful in the industry. Both are major buyers of Boeing planes, with Southwest continuing to maintain an all-Boeing fleet even once it closes on its Airtran acquisition. The hole that developed in the fuselage of a Southwest 737 on a April 1 flight threw the company’s relationship with the manufacturer into question. Kelly repeatedly said Boeing and Southwest were working to make sure the unexpected problem was fixed, and he broke no new ground on the controversy.

But both he and Arpey said they had concerns about other issues with Boeing. Southwest wants to continue buying and flying narrow-body airplanes, but Boeing is cutting production, Kelly said. Arpey’s American is waiting on its first Boeing 787, which has suffered numerous production delays.

“It’s very frustrating for us, and I don’t want to let Boeing off the hook,” he said. “But we have great confidence that Boeing is going to make a great airplane.”

American has dozens of new 737s either in flight or on order, and the aircraft type will surpass the number of MD-80s in American’s fleet next year, Arpey said. The MD-80 has been American’s workhorse airplane for three decades.

While Southwest has turned machine-like profits, American didn’t have positive net income in 2010. Arpey said the other legacy airlines have been able to restructure their costs in bankruptcy, while American has not.

“Many of those advantages are not permanent,” he said. “We’ll have a competitive cost structure after the next round of labor negotiations.”

Additionally, Arpey and Kelly both said the nation’s air traffic control system needs to be modernized.

“You can’t find anyone who says it doesn’t need to be done — it just needs to get done,” Kelly said, adding that he thinks a 15 percent fuel cost savings by modernizing air traffic control is a conservative estimate.

NEXT: Elizabeth Warren, President Obama’s consumer-credit czar, will speak at the conference.

PREVIOUS: Dallas Fed Chairman Richard Fisher says fuel exists for private sector job growth, but Congress must fix fiscal policy first.