Tag: boarding flights

Guest Post: Southwest Airlines’ Boarding Overhaul–When Queuing Theory Takes Flight

Providence College Professor Jon Jackson discusses a topic that every flier understands.

For over 50 years, Southwest Airlines has stood out with its open seating policy—passengers lined up, boarded in order, and picked any available seat. That system will soon end. Starting in January, Southwest will introduce assigned seating and its first premium seats, as part of a major redesign of its boarding process. Internally called “Project USA,” this initiative is more than a marketing shift—it’s a deep operational rethink based on one principle: if queuing isn’t good, boarding isn’t good.

Southwest’s new boarding plan is a live experiment in queuing theory and process design, balancing efficiency with customer experience. Boarding is a significant driver of turnaround time—a key metric for airlines. Every minute saved at the gate means higher aircraft utilization, lower fuel costs, and better schedule reliability, writes The Wall Street Journal (Oct 13, 2025).

Astrophysicist Jason Steffen’s boarding process, which boards passengers in a diagonal pattern, minimizes blocking and maximizes parallel activity. Simulations suggest it could reduce boarding times by 30–50%, but it relies on strict compliance and passenger discipline—hard to guarantee in practice.

Southwest’s new system will use a variation of the WILMA method—boarding Window, then Middle, then Aisle seats—to reduce aisle interference and speed up boarding. This approach is validated by queuing research, though the Steffen process is even more efficient in theory.

Boarding an aircraft is fundamentally a queuing problem—a test of bottlenecks, flow efficiency, and human behavior. The new plan introduces nine boarding groups and two parallel lines to create a smoother, more predictable flow.

Classroom Discussion Questions
1. How do the WILMA and Steffen boarding processes differ in terms of efficiency, complexity, and customer experience? Why might Southwest choose a simplified version rather than the most efficient theoretical model?
2. What behavioral factors might reduce the effectiveness of Southwest’s new boarding plan, and how could the airline design around them?

OM in the News: The Boarding Logjam

The glacial pace of boarding planes irritates frequent fliers and airline employees, writes The Wall Street Journal (March 3, 2023). Along with other preflight requirements, it also adds costly time on the ground for Southwest and other airlines, which regularly study ways to speed up boarding.

Southwest employees carry mobile devices to speed up processes such as checking bags.

Today, Southwest is on a mission to shave 5 minutes off the time a plane spends at the gate between flights. The average “turn’’ is now 40 minutes for its smaller Boeing 737s and 50 for the larger ones. “If you can collect up enough of these minutes in each turn, then you can start to squeeze out some more flying,’’ says Southwest’s COO.

Research shows boarding bottlenecks are the biggest detriment to turnaround times. Delays in seconds between passengers finding their seats, or sitting in the wrong seat, add up fast. Southwest is testing 11 concepts at four gates at the Atlanta airport. Signs tell passengers they are entering an “innovation zone.’’ The Atlanta project is a big component of Southwest’s 5-minute quest, with goals of saving 2-3 minutes on boarding per flight. Southwest hopes the rest of the time savings can come from efforts including bigger overhead bins, a possible increase in boarding planes from the front and back simultaneously, and paperless takeoff documents.

One of the biggest changes: The stanchions where passengers line up to board have video monitors. They display a boarding countdown, an alert when important announcements are being made and flashing lights when boarding begins. Southwest is also testing a designated preboarding area for passengers in wheelchairs and families boarding together, a staging area it hopes will reduce gate crowding. It went so far as to test different carpet colors for each area—yellow is out because it showed stains.

Southwest brought music to the jet bridge because the team’s research found people move faster to up-tempo music. Preliminary results show the music and prerecorded jet bridge announcements about bin space, seat availability and other information are helping. They answer the questions flight attendants say they hear over and over again during boarding.

Classroom discussion questions:

  1. What other suggestions do you have to speed up the boarding process?
  2.  What tools for process analysis in Chapter 7 of your Heizer/Render/Munson text can be applied in  a case like this?

OM in the News: Boarding Airplanes and Operations Management

Delta is testing new boarding procedures to line people up in an orderly way instead of the pack seen at this boarding gate in Atlanta

One of the thorniest operations management problems in air travel is stumping carriers: How best to board a plane? “Boarding has gotten slower and far more stressful,” writes The Wall Street Journal (March 2, 2017). Airlines are trying to end the mob mentality at boarding gates, where passengers crowd the gate, sometimes pushing and blocking the way for people who have been called to board.

Delta is testing new boarding lanes and monitors in gate areas that bring more order to boarding turbulence and shave 30-60 seconds off a flight. That’s a huge saving for an airline with thousands of flights scheduled daily. “All the studies say the quickest boarding process is just open the door and let ‘em go, and people just pressure one another,” says Delta’s VP. “But it’s not a very good customer experience.” Passengers say airlines created the problem with checked-baggage fees that lead people to carry on more.

The old method of back-to-front boarding by row number was standard for decades but proved slow. Same with boarding passengers in window seats first, then middle, then aisles seats. Random turns out to be a better way to single-file travelers to their seats. Multiple people in the line reach their rows at the same time. But random fell victim to privilege. Multiple levels of elite status get priority. (70-80% of passengers on a flight may have elite status.)

American’s OM staff recently spent time observing Southwest’s boarding system, generally considered fastest. Southwest assigns each passenger a number, then lines everyone up in sequence. Passengers know where and when to stand. They have incentive to move quickly to pick an open seat. “It’s pretty clear Southwest does it best,” says a UNLV expert on planetary systems who got curious about earthbound airplane boarding systems and conducted a study looking for an ideal solution. (His answer: Board 10 passengers at a time in alternating rows.)

Classroom discussion questions:

1.What OM techniques can be used to study this problem?

2. What other suggestions do your students have?

OM in the News: Speeding Up the Airline Boarding Process

delta air“Airlines are trying to save time by speeding up a part of flying that creates delays even before the plane leaves the gate: the boarding process,” writes US News &World Report (June 1, 2015). This summer, Delta plans to preload carry-on bags above passengers’ seats on some flights. Southwest wants to get families seated together more quickly. No perfect boarding method has ever emerged.

Most airlines let first-class and elite customers board first. After that, some fill the rear rows and work toward the front. Others fill window seats and work toward the aisle. Airlines have also tried letting people board early if they do not have carry-on bags. Slow boarding creates delays, which mean missed connections, unhappy customers and extra costs. Researchers figure that every extra minute a plane stands idle at the gate adds $30 in costs. About 1 in 4 U.S. flights runs at least 15 minutes late. With 1,000s of flights each day, costs quickly add up.

Delta’s Early Valet service will offer to have airline employees take carry-on bags at the gate and put them in the bins above assigned seats. The airline wants to see if its own workers can load the bins faster than passengers. The service began Monday on 2 dozen flights, and that number is expected to rise steadily, adding departures from Atlanta, New York, Los Angeles, Detroit, Minneapolis, Salt Lake City and Seattle. Delta tested the process last summer and saw some reduction in boarding time.

Meanwhile, Southwest Airlines wants to reduce complaints that families can’t find seats together because flights are so crowded. Southwest passengers line up at the gate by group — first “A,” then “B” and finally “C” — and pick their seat once they are on the plane. The system lets families board together after the “A” group, but only with children up to 4. Some families pay extra for priority boarding to improve their odds. Southwest recently tested expanding family boarding to include children up to 6, 8 or 11.

Classroom discussion questions:

1. What other processes can airlines use to speed boarding?

2. What process and design techniques in Chapter 7 can be used for this process?

OM in the News: Speeding Up the Airline Boarding Process

Barry and Jay at Alaska Airlines
Barry and Jay at Alaska Airlines

Jay and I just returned from a visit to Alaska Airlines headquarters, where we studied the intricacies of operations management at the top-rated U.S. carrier.  One of the many issues we discussed was the speed of boarding passengers onto their flights.

In the past 3 decades, the airplane boarding process has become an increasingly important industry-wide issue for airlines and passengers. Prior to 1970, the average boarding speed of passengers nationwide was 20 passengers per minute. By 1998, this rate had decreased to 9 per minute. The increased costs of checking luggage will continue to play an important role in the time to board, as passengers are going to respond to increasing fees by carrying more bags onto the plane. As a result, the boarding speed may continue to decrease.

When using an average boarding strategy, the difference in boarding times when passengers have 2 carry-on bags compared to zero is almost 60%. Long boarding times impact costs. The total cost of airline delays in 2007 was estimated to be $29 billion in the U.S. alone, with the cost to airlines ($8 billion), the cost to passengers ($17 billion), and the cost from lost demand ($4 billion). This indicates the possibility for large savings for the airlines and passengers with more efficient boarding methods.

Seattle airportSo a recent article by Clarkson University researchers to develop a strategy for boarding flights caught our eyes. The new method, published in the Journal of Air Transport Management (Jan., 2014), assigns airline passengers to a specific seat based on the number of bags they carry, causing luggage to be evenly distributed through the plane. Each row of seats would tend to have a passenger with 2 bags, a passenger with 1 bag and a passenger with no bags. “The new method would save at least several seconds in boarding time and prevent any one area of the plane from becoming overloaded with bags,” says author Prof. John Milne. “Airlines could provide a smoother boarding experience for passengers by utilizing the research.”

Classroom discussion questions:

1. Why is boarding an OM issue and what control do managers have over the process?

2. What other boarding procedures are in place across the industry?

OM in the News: New Looks at Loading and Boarding Planes

alaska air jetwayLoading an airplane quickly and efficiently isn’t an easy task. “It should be, and could be, but the humans involved can’t seem to get with the program,” writes Wired Magazine (Aug. 28, 2013). Better loading means more time in the air – which is where airlines make their money. The boarding process is far from standard – there are almost as many boarding procedures as there are airlines. This problem has long been pondered by operations managers, without a definitive answer. But there have been a few promising experiments.

The most unusual and deceptively simple idea is opening the door at the rear of the plane in addition to the door at the front. Alaska Airlines is trying this. The idea isn’t entirely new–many airlines open the front and rear doors at those airports where there is no jetway, only a staircase leading to the tarmac. Alaska has a new tool to help facilitate using both doors–a solar-powered ramp. Mounted on wheels, the ramp can be driven to the backdoor of the airplane, and passengers make two switch-back turns down the ramp to the ground, providing an alternative to stairs for easy suitcase rolling and wheelchair access. Using the aft door to unload passengers can reduce the turnaround time by 10 minutes.

One of the big reasons boarding has slowed to a crawl is people are carrying more bags aboard to avoid baggage fees. So American Airlines is experimenting with letting those who checked their bag board first. Ideally, these passengers will simply walk to their row and sit down. The airline says that overall it has shaved a few minutes off the boarding process.

Although airlines commonly board by sections, it’s generally a free-for-all with regard to where in that section you are. United uses the “outside-in” method of seating window passengers first, then middle, then aisle seats. The airline has been organizing passengers in better defined lines at the gate for each group, with the hope is there will be less of a bottleneck.

Discussion questions:

1. Why is boarding an important OM issue?

2. What else can airlines do to speed the process?

OM in the News: Is Boarding the Most Annoying Airline Delay?

I guess the answer is yes, given that yesterday’s New York Times (Nov. 1, 2011) ran a front page article on the woes of airline boarding.  Airlines have been complicating the process of boarding  for decades, writes the Times. First travelers have to be sorted by priority: 1st class, frequent flyers, elite cardholders, military in uniform, families with kids, and so on. Then there is the issue of seats  for those who paid priority boarding fees, the matter of more roll-ons in the aisle from checked-baggage fees, and of course,  the fact that planes are fuller. Boarding time has actually doubled— and it now takes 30-40 minutes to board 140 passengers, up from 15 minutes about 20 years ago.

 Operations scheduling techniques (Ch.15) have been used by every airline to find creative solutions to speed boarding. Spirit Airlines says the answer is to charge $20-$40 per carry-on bag. This “stress-free” boarding saves 6 minutes on average. American Airlines switched a few months ago to boarding passengers earlier who pay $9-$19 extra (and hence find a space for their bag). The rest of the passengers are brought in as 3 groups, sorted out in a spread throughout the plane. This method has cut boarding by 4-5 minutes.

US Airways hired ASU profs to develop a “reverse pyramid” to save time. Passengers with window seats in the back board first. Then, gradually, passengers are brought on to the front of the plane in a staggered pattern. Southwest, which can board its planes in 15 minutes, claims the root of delays is the practice of assigning seat numbers. So it assigns passengers to one of 3 boarding groups.

The conflict: all the extra fees for early boarding and baggage will add $12.5 billion to the bottom  line of US airlines this  year, up 87%  from last year.

Discussion questions:

1. Research has shown that “back-to-front” boarding is the slowest method. Why is it still used?

2. How else can OM help solve this problem?