Airlines want to board planes quickly. A short delay has knock-on effects, because the next flight is likely delayed and the next flight. Passengers miss their connections, bags don’t make their next flight either, and crew delayed on one flight delay other flights too (and may even reach their maximum duty hours for the day, leading to cancelled flights).
So the science of how to board a plane quickly matters a great deal to the bottom line. Southwest Airlines has said it would cost them 8-10 planes per day just to add “a couple of minutes of block time to each flight in our schedule.”
Every so often airlines tinker with their boarding process, trying to speed things up. Southwest tends to board quickly because the order in which a passenger boards determines where they’ll sit on the plane. So they show up at the gate 30 minutes before their flight and they line up in a usually orderly fashion. Airlines with assigned seating do not have that advantage.
One study found an optimal board process would be to board
passengers in a series of waves, with the first passengers called to board seated in window seats two rows apart—first 30A, then 28A, then 26A and so on. Next, the same for the other side of the plane (30F, 28F, 26F). The process continues with odd row window seats on either side, middle seats, and finally aisle seats. Each person can sit down within moments of one another without getting in anyone’s way. In field tests, it proved to be almost twice as fast as most conventional methods, and 20% to 30% faster than have-at-it, entirely random boarding—which is also faster than the method used by airlines. (He too would board slower passengers requiring assistance first.)
In the real world you can’t do that. Doug Parker explains that there are customer considerations, and you can’t just do whatever is best for fast boarding. Especially now you want to socially distance passengers during the boarding process, even if most airlines are no longer blocking seats and planes are increasingly full.
He explained in a meeting with flight attendants earlier in the month why American Airlines won’t move to ‘back-to-front’ boarding despite its intuitive appeal:
We have looked at that, we’ve studied it, and while it may seem better to have people go from back to front ..what you really want to do is window-to-aisle but if you do that you split up families and things.
When you do back-to-front there is just as much if not even more in some cases interaction with customers getting up and out of the aisle as there is with our process.
So what we choose to do instead is tell our frequent flyers – our elite customers – they can board whenever they like and then we use our normal boarding process.
And then we ask when you leave, because we have everyone actually window-to-aisle and they’ll leave properly..but we’ve seen no increase in the lack of close interaction by going back-to-front versus the process we use.
..We’ve studied this with operations engineers who go look and watch and we don’t see any material change and in some cases more interaction.
You can’t split up families, so the ‘theoretically best boarding order’ doesn’t work. And back-to-front leads to bunching as well. And since those don’t work out as well in practice as in theory, their regular boarding process stands.
This is why airlines all tinker with their process from time to time and never stop tinkering, because they’re never been able to do much to improve – with few exceptions.
In the early days of Southwest Airlines they struggled financially and returned one of their planes. They kept the bulk of their schedule despite having one fewer aircraft. And to do that they needed to turn planes in 10 minutes. Passengers were deplaning out the rear of the aircraft while new passengers were getting on. Southwest’s cabin crew even do light cleaning of the aircraft between flights.