Most US airlines follow the same procedure for allowing non-first-class passengers to board a plane. They let people who are sitting in the back board first, then people in the next few rows, gradually working their way toward the front.
This procedure makes absolutely no sense.
“The Data shows this is not a good way to board an airplane”
If asked to devise a boarding method without any data, you might settle on this as a pretty sensible one. But the airlines do have data — and numerous studies have shown this is not a good way to board an airplane, in terms of time or customer satisfaction.
The fastest ways to board a plane are Southwest’s boarding method — where people choose their own seats — or a theoretical boarding method known as the “Steffen method” that’s not currently in use.
Both simulations and real-life experiments have proven the standard method to be the slowest out of several different ones. In 2012, the TV show “Mythbusters” recruited 173 people to compare four methods in a replica airplane interior and found that Southwest’s boarding method was the fastest. A close second was allowing all windows seats to board first, then all middles, then all aisles (outside-in).
This article has a very interesting video illustration.