Southwest is changing how it boards planes, but don’t expect it to be faster

It’s an important week for Southwest Airlines, as the carrier prepares to announce more details about its move away from the open seating model that’s long been its trademark.

That's a major change for the Dallas-based carrier — one that Southwest has been considering since at least 2006.

“It was a secret project. We had to use code words when we talked about it,” says Doug Lawson, who worked for Southwest for more than 20 years, mostly in operations.

Southwest is well known for turning its planes around faster than its competitors, in part by letting passengers pick any open seat during boarding. But its leaders wanted to know if there was an even faster way: boarding the plane from the outside in, window seats, followed by middle seats, followed by aisle seats, sometimes known by the acronym WILMA.

It was so controversial, Lawson says it had to be kept secret — even inside Southwest. “The code name was D WILMA,” Lawson said in an interview. “The D stands for ‘Doug.’ My boss couldn’t think of anything more original,” he chuckled.

Eventually Southwest lifted the veil of secrecy with a real-world experiment at San Diego International Airport in 2006, and invited the media (including NPR) to watch.

Part of the time, the passengers boarded the regular Southwest way, with open seating. And part of the time, they had assigned seats according to the WILMA plan. In the end, Lawson recalls, there was a clear winner: WILMA.

“It was like a 20% difference,” Lawson said. “That’s huge. It’s a very significant operational improvement.”

Still, Southwest decided to stick with open seating. Lawson says company leaders at the time were worried about the damage the switch might do to the brand.

Back then, Southwest was focused on keeping its planes in the air because they don’t make money sitting on the ground. But a lot has changed in the airline industry, as carriers look to maximize profit — even if that makes the boarding process slower.

“This is what our customers want,” Southwest CEO Bob Jordan told CNBC in July. “80% of customers that fly Southwest said they wanted an assigned seat… And when a customer defects from Southwest to another competitor, it's the number one reason.”

It’s not just that customers like picking their seats. Airlines have discovered they can make money by selling them at a premium. They’re also putting more emphasis on loyalty programs that reward their best customers with perks like early boarding.

“There is a sweet spot for the airlines they are looking for here,” said Ahmed Abdelghany, a professor at Embry-Riddle Aeronautical University who used to work in operations at United Airlines.

“I want to make money," Abdelghany said. "I want to be efficient. And at the same time, I want to please my customers.”

There’s been no shortage of research over the years on the fastest way to board planes. Back in 2005, an astrophysicist named Jason Steffen started working on the problem after getting stuck in a long boarding line. Steffen, who’s now a professor at the University of Nevada, Las Vegas, submitted his paper "Optimal Boarding Method for Airline Passengers" to the Journal of Air Transport Management.

“The fastest way to board people is you send them in so that each successive passenger has sufficient room to put their luggage away without bumping into their neighbors,” Steffen said in an interview.

Steffen’s method involves alternating which rows are boarding so that passengers have more room, while also boarding each row from the outside of the plane in.

“You get people into the airplane and you minimize the number of aisle interferences,” Steffen said. “And then the next most important interference is the seat interferences where you have to jump over somebody.”

Some airlines have adopted parts of Steffen’s approach. United, for example, has incorporated WILMA principles into its boarding process — although fliers with more status still get to board first. That means more passengers have to get out of the way to let others reach their seats, which tends to slow the process down.

Other airlines have decided that those few minutes of efficiency are simply not worth the trouble.

“The biggest obstacle is just the unpredictability of human behavior,” said Greg Forbes, managing director of airport experience for Delta Air Lines.

In theory, Forbes believes Delta probably could save a few more minutes boarding its planes. But he says these intricate plans don’t always work in the real world, where passengers show up late, with lots of carry-on bags, and sometimes board in the wrong order.

“All these things would probably pick up a minute or two, but you would give it back up as soon as someone forgot their headphones in their bag or were struggling to get a bag to fit in the overhead,” Forbes said. “I think that the last minute of optimization would come at a price of consistency, reliability and stress.”

It’s not clear how Southwest will approach assigned seating. The airline says it will announce more details at an investor event on Thursday.

Former Southwest employee Doug Lawson says the company has not told him what it's planning. Lawson, who now works as a consultant, says the end of open seating took him by surprise. It’s still faster than many boarding strategies, he says, because it tries to embrace human behavior instead of fighting against it.

“When you think about it, that's why open seating is fast. People don't want to sit in the middle seat. So there's almost never a case of two people getting up to let somebody sit down,” Lawson said. “So you take advantage of the behavior of people, right?”

Open seating was once a crucial part of Southwest’s financial success, says Jody Hoffer Gittell, a professor at Brandeis University and the author of The Southwest Airlines Way. But it always depended on the cooperation of the airline’s passengers to make it work.

“It could be that maybe passengers are not as willing to cooperate in getting seated. That kind of ability to get passengers sort of motivated to self-organize was really critical to that strategy,” Gittell said.

Indeed, some longtime Southwest customers complain that other passengers have been gaming the open seating system by boarding early and saving seats.

Gittell speculates that open seating simply isn’t working as well as in a society that’s deeply divided.

“It could be hard to orchestrate that kind of good-natured, ‘let's get on there fast, and I'm going to grab this seat, and you grab that seat,’” she said. “There's a collaboration involved and a co-production by the customers that makes that possible. And pulling it off in our current culture could be a challenge.”