With more and more Web sites offering to help passengers buck Southwest Airlines' first-come, first-serve boarding process to lock in a coveted window or aisle seat for a fee, the discount carrier has turned to the courts to protect its one-of-a-kind system.
The carrier has written to about a dozen sites asking them to shut down, and last month sued one that refused to close, BoardFirst.com, in federal District Court in Dallas.
The online sites charge passengers about $5 to check in 24 hours before a flight, when the airline first permits it. The first 45 passengers in line -- a third of a plane's load -- get an "A" pass that gets them to the front of the line to board. Passengers can check in themselves online, but the sites effectively do it for them.
The lawsuit caught the founder of BoardFirst off guard.
"We are only helping Southwest passengers, and making their flying experience a little more pleasant," said Kate Bell. "Southwest should be embracing us, not trying to shut us down."
Southwest did not try and stop Bell at first, although officials expressed unease at the launch of the service in October because they couldn't control it and feared passenger information would be sold or used inappropriately.
Southwest does not participate in outside booking services such as Travelocity or Orbitz because the carrier says it wouldn't be able to control how its passengers are served.
Southwest officials also didn't believe many passengers of the discount airline would pay the $5 Bell was getting for each A pass. But when other sites began cropping up and customers started complaining they would have to pay, too, Southwest saw a problem.
The Web sites saw themselves as just another example of the Internet entrepreneurs that have proliferated in recent years. Travel services offer everything online from helping a passenger find cheap fares to notifying his business partners and family when his flight is delayed to securing a hotel and rental cars.
And Southwest itself steers passengers to the Web. Close to 70 percent of Southwest's revenue now comes from online bookings and half the airline's customers check in online. It even has launched a blog where customers can vent about seating and other things.
"We thought this is capitalism. This is America," said Matt Bousky, a founder of APassOnly.com, which has agreed to shutdown. "Southwest thinks they are this great big democracy in the sky, with nobody treated special. We were treating a few people special for $2.50."
Southwest called it something else: breach of contract and unfair competition.
The airline acknowledges that not everyone likes its boarding system. And that is why it began allowing the online check-in for those with a preference.
And the company is working on changing its reservations system over the next year or two to accommodate assigned seating, though the airline won't promise that it ever will change. It is the last major airline that does not assign seats.
The system has become familiar at airports because passengers typically form three lines based on check-in times ahead of each flight at the gate, prompting comparisons to cattle.
It works for the airline by allowing it to board passengers quickly and fly more planes per gate per day.
Airline officials insist many customers don't mind the system. The company blog offers passenger testimonials of support such as this one: "Please don't consider going to assigned seating. There are lots of us who like things just the way they are now."
Bousky, who launched APassOnly in January with a group of travel agents, lawyers and computer whizzes, said he has his own testimonial e-mails from customers.
"As a Southwest Airlines frequent flyer I am outraged at Southwest threatening legal action against you for providing an invaluable service. I take this as an insult to me directly, as I reserve the prerogative as to which way I want my boarding pass retrieved. If I ask my secretary to retrieve my pass, I insist on the liberty to do that; if I want my spouse to retrieve it, I insist on the liberty to do that. If I want APassOnly to retrieve it, then I reserve the liberty to do it that way," read one e-mail.
Bousky said his customers say they can't always be at the computer a day ahead of a flight. He envisioned expanding the service to other concierge services, such as reserving tee times on the golf course, but those plans are on hold. He is now providing his service only to those who have already paid for it. So far he's been rebuffed in his efforts to sell the computer program to Southwest.
He believes all the Web sites captured no more than 300 of the estimated 140,000 A passes the airline could hand out daily, assuming the carrier's 3,100 daily flights are full.
But Brandy King, a Southwest spokeswoman, said the sites were popping up "almost daily."
"We're running the risk of losing track of our own inventory," she said. "We've heard from customers who are worried they will have to pay a third party for an A pass. In order to protect the product and the brand and our customers, we had to do something."
Southwest relied on the "terms and conditions" of its tickets, which forbid third parties from using its Web site for commercial purposes.
They have the legal leg up, said Anthony M. Sabino, an airline industry expert and law professor at St. John's University's Peter J. Tobin College of Business in New York.
Unlike airlines that sign onto Travelocity, Orbitz or Priceline, which find passengers cheap flights, Southwest has chosen not to participate.
"The guy hanging on and fighting this is going to lose," he said. "In other instances such as with Travelocity there is a contractual and legally binding agreement. Southwest hasn't signed on for that and no one can make them. You just can't set yourself up to be the middleman. You're infringing on proprietary information and function."
No court date has been set.