One of Southwest Airlines’ mantras really bugs business traveler Robert Scott.

“We’re not all things to all people,” Southwest Airlines chief executive Gary Kelly has been known to say.

Scott fears he’s one of the “all people” Kelly means. That’s because when Southwest fully absorbs AirTran, he’ll no longer be able to book the business class seats he loves — at least not on AirTran-turned-Southwest.

As welcome as Southwest’s arrival in Atlanta may be to many fliers, some business fliers such as Scott fear they will face reduced choices. AirTran had a hybrid service model of low fares coupled with mainstream service, including business class and traditional assigned seating. Southwest has neither.

“I’ll miss AirTran a lot,” Scott said. “I liked having an assigned seat and being able to go in business class for not a lot of money.” In the future, he added, “I’ll probably fly Delta a lot more.”

Chris McGinnis, editor of The Ticket newsletter for Atlanta business travelers, said the lack of a business-class seating option is “the biggest obstacle Southwest is going to face in Atlanta ... Everybody’s up in arms over that.”

Southwest spokesman Chris Mainz said AirTran loyalists may not be used to Southwest’s style of operating but may come to like it.

“AirTran has a very loyal following, and they’re used to the services and the style that AirTran operates,” Mainz said. “We strongly feel that once they do experience Southwest service, they’ll come to appreciate it as much as our current loyal business travelers do.”

Southwest executives often point to the airline’s overall success and steady growth in passenger counts as evidence of the wisdom of their approach.

“We’re very confident in our product,” Mainz said. “We encourage and invite them to fly Southwest Airlines, then let them decide if it’s the right choice for them.”

In selling itself to Atlanta Southwest is likely to tout is its lack of checked baggage fees. Yet that won’t benefit business travelers who travel light or got free baggage check due to elite frequent flier status.

Although AirTran started out as a no-frills carrier, over the years it added full-service perks in order to win a chunk of the business travel market, which is typically a big profit center for airlines because such travelers book less-restricted, more expensive fares.

Mainz said Southwest is listening to AirTran business travelers. “We do value their feedback,” he said. Attracting business travelers has been a big focus for Southwest recently, and “any decision that we make, we have the business traveler in mind,” Mainz said.

Kelly, the CEO, has said Southwest arguably carries more business travelers than rivals because of its sheer size as the largest U.S. carrier in the domestic market. He’s also acknowledged the airline loses out on some business travel and wants to change that.

“Whether we’ll get our ‘fair share’ eventually, I don’t know. But we’ve got a long way to go,” he told analysts recently.

McGinnis expects that the removal of AirTran’s business class will lead to some higher first class fares and less room for upgrades on Delta.

Southwest also plans to end AirTran’s assigned seating, further irking some AirTran frequent fliers.

“When you spend your entire life on a plane, you kind of get particular about what you want,” said one, Don Turner. He commutes weekly to California and said he needs a seat with space to be comfortable and to work on the plane.

“I think there are some real fans [of Southwest] who are used to getting on the plane in sweatpants and reading a book,” he said. “They’re not really expecting to work.”

Southwest is showing more flexibility in other areas with the acquisition. For instance, it has only flown 737s throughout its history, a practice that keeps fleet management simpler and less costly. But it will inherit smaller Boeing 717s in the AirTran deal. It also will take over some of AirTran’s Caribbean routes, which will be its first outside the U.S. And it is taking over a full-blown connecting hub in Atlanta after decades of eschewing the connecting hub model.

Turner and a number of other AirTran business travelers are taking a wait-and-see approach, or planning to fly carriers with a traditional approach.

“I’ve got nothing against [Southwest],” Turner said. “[Southwest] just doesn’t fit my travel requirements.”

Joe Leader organized a “Save our Seats” campaign among AirTran frequent fliers to try to persuade Southwest to keep business class and assigned seats.

“The times I flew Southwest when it was genuinely cattle call, I really disliked it,” said Leader, of Dunwoody, who is president of a trade association. “I’ve heard that it’s gotten better recently. I won’t believe it till I see it.”

Ron DiLeo, executive director of the Association of Corporate Travel Executives, takes a more measured view. “Where I think it will be positive for business travelers is Southwest has a huge network ... It’ll be easier for you to stick to one airline” than it was with AirTran.

Meanwhile, Delta has launched a campaign in Atlanta emphasizing its 70 years as “Atlanta’s hometown airline” — a message that might resonate when it goes up against the mega discounter from Texas. And Delta has been promoting the addition of first-class seats on more planes, including some regional jets.

Alan Bender, a professor at Embry-Riddle Aeronautical University, said some businesspeople, such as sales people and entrepreneurs, still will gravitate to Southwest because cost and convenience is more important to them than perks.

“What’s important on a one-hour flight is who has the next flight out,” Bender said.

Terry Sherwin, an insurance broker based in Smyrna, liked getting upgraded to business class on AirTran as an elite frequent flier, but he’s willing to give Southwest a try.

“I’m going to try them first, and if I don’t like them, I’ll probably go back to Delta,” Sherwin said.