# It’s time to fix how we board airplanes

I travel often enough that when people ask me where I’m based, I sometimes joke “Seat 4F.”

I’ve been able to observe a lot of passengers boarding planes. Based on what I’ve seen, how we board airplanes doesn’t work very well. And based on what I’ve read, it doesn’t make sense either.

All U.S. airlines allow first class, business class, and their most frequent flyers to board before everyone else. In addition, some airlines sell priority boarding for an additional fee. Most airlines board everyone else in the same way: passengers sitting in the very back board first, with more passengers allowed on the plane gradually from back to front.

Monte Carlo simulations have shown this is an inefficient method. Mathematically, whenever a passenger tries to sit down, there’s a 1 in 3 chance that someone will already be seated in that row and have to get up to let the new passenger in – this slows things down. In addition, most of the people boarding are around the same rows and trying to use the same overhead bins so there is lots of congestion in the aisle. This video simulation shows the congestion well:

United Airlines uses an outside-in boarding process which allows everyone with window seats to board first, regardless of row. After that, all people with middle seats board and then all people with aisle seats. United refers to this as “WilMA” (Window, Middle, Aisle).

An episode of Mythbusters showed this process is nearly 50% better than the more common back-to-front because it reduced congestion in the aisles. The downside of outside-in is that passengers sitting together can’t board at the same time. This could be a problem for families with young children which is likely why United allows them to board earlier.

Outside-in is faster than back-to-front but the unassigned seat method used by Southwest Airlines is even faster (but not by much). Passengers board in order of check-in but, since they have no assigned seat, can sit wherever they like. People naturally avoid congestion and navigate to open rows. While the unassigned seat method is slightly faster than outside-in, it leads to lower customer satisfaction scores. Many people, including me, like to know where they are going to sit before they board – especially if they are travelling with others.

The best boarding method might be a debate between outside-in and unassigned seat assignments if not for a physicist named Jason Steffen. Steffen’s method essentially combines outside-in and back-to-front; instead of window seat passengers boarding in any order they want, they board back to front. After widow seats, middle and then inside seat passengers board back to front. An episode of the PBS series Making Stuff Faster tested the Steffen method as 25% faster than Southwest’s unassigned seat technique – making it the fastest known method.

There are three boarding techniques which are all significantly faster than the commonly used back-to-front method. So why don’t the airlines switch? It could be nothing more than an unwillingness to change. Or maybe it’s because more and more passengers are paying an additional fee to board early.

What do you think?

### 5 Responses to It’s time to fix how we board airplanes

1. Mukesh Gupta February 12, 2017 at 9:47 pm #

Amazing stuff… This is so simple yet can have a profound impact not just on the customer satisfaction but also on the airlines bottom line as it could mean a couple of additional flights per carrier in a year (at least)..

2. Eisaiah Engel February 13, 2017 at 6:14 am #

On my last flight from LAX to DFW, the flight attendant clicked the button on the loudspeaker and announced, “We are boarding zone A.” I was in zone C. I got up to follow the herd. So did other passengers in zones C, D and B. What drove us to stand up even though it wasn’t our turn? Fear of being left out. The inside of an airplane is not an environment where many people spend time. People crave certainty in unfamiliar environments. Early boarding and a seat toward the front provide certainty. This is the natural flow of human behavior, which airlines seem content to monetize with front to back boarding. Perhaps in the big picture, front to back is not the most profitable way to board even with upselling. But you know, airlines…

3. Annie M Hayward February 13, 2017 at 7:26 am #

Quite interesting. I think back-to-front has merits, as long as the economy passengers don’t get to take up overhead space in the Biz/First Class sections. The value to 1st & biz class folks could be: you don’t have to be at the gate right at boarding time.

What I think more experiments might be needed is the de-plane portion. There is rampant impatience once the plane lands. Everyone is up, and the aisles can be cluttered with people whose overhead is elsewhere. Wouldn’t a de-plane by rows be more orderly? Just a thought.

• Eisaiah Engel February 13, 2017 at 8:32 am #

Yes. The deplane process is more painful and needs work.

4. Rob Holland February 13, 2017 at 8:13 am #

The biggest challenges to efficient boarding are airline club status and overhead bin space.

One of the things I’ve found most frustrating recently, ironically when boarding a United flight, was that even though I’d paid for a seat upgrade, I didn’t get to board until everyone with status had done so – regardless of where they sat on the plane. This meant that I had to gate check my carry on despite having paid extra for my seat. And this was after about 45 minutes of waiting which is far longer than any Southwest flight I’ve ever taken. As long as airlines have programs that award people with status with early boarding, we’re never going to get close to efficient boarding.

Similarly with overhead bin space. Passengers who pay anything additional for seating, whether that be first, business, or some sort of preferred economy, expect to be able to board a plane and have overheard bin space. Typically the most efficient boarding methodologies cannot guarantee anyone wanting to carry on bags being able to do so.

Perhaps a solution to this would be to make all the preferential seating at the back of the plane, though unless there is also a corresponding ability to get off earlier, I can’t see that being terribly popular.