Do airlines literally want boarding to be a pain? The science points to yes.

There are plenty of ways you can control the quality of time and money you spend on air travel—from choosing the best seat on an airplane, to following the best day to buy plane tickets, to avoiding the most germ-ridden reaches of the plane. One thing you can’t control, sadly, is one of the biggest time sucks of air travel: how the passengers board the plane.

Various airlines rely on various methods for boarding their passengers, but an overwhelming majority (including American, Spirit, JetBlue, and Virgin) use the least-efficient method—back-to-front. After First and Business class passengers take their seats, passengers board by zones, typically beginning in the back of the place and moving toward the front of the economy cabin. This makes sense, in theory (passengers seated further back won’t get in the way of passengers seated toward the front) but in practice it couldn’t be worse. According to a series of simulations run by TV’s Mythbusters, it is literally faster to board the plane completely randomly; the back-to-front method took an average of 24 minutes and 29 seconds to get every passenger seated, while filling seats at random only took 17 minutes, 15 seconds.

Why is back-to-front so inefficient? The method doesn’t account for the inevitable bottleneck of passengers that occurs in the aisle of the plane while everyone is trying to cram their carry-on into the same overhead areas. When the aisle backs up, the airbridge backs up, and when the airbridge backs up, the queue at the gate backs up, and when the queue at the gate backs up, dad’s coffee gets cold, and now everyone can expect five hours of seething grump. Lose, lose, lose.

Surprisingly, only one airline is known for using the scientifically-proven, fastest method of passenger boarding: Southwest airlines. For decades (since 1971), Southwest has held to the method of not giving passengers assigned seats. While this rates low in passenger satisfaction (according to Mythbusters, it was the least-liked method of the four they tried), allowing customers to board in the order they checked in and grab seats in a free-for-all fashion only took an average of 14 minutes, 7 seconds—a full 42 percent faster than the favored back-to-front style.

It’s interesting to note that the plane-boarding method that rated highest in customer satisfaction only took a few seconds longer than the free-for-all. The “WilMA” method (which stands for Window, Middle, Aisle) boldly boards all passengers in window seats first, followed by middle seats, and finally aisle seats (though airlines like United, who favors this method, do make special accommodations for families boarding together). Mythbusters found the WilMa method only took 14 minutes and 55 seconds, making it both efficient and crowd-pleasing.

So, why is United the only major airline to give WilMA its due, and why don’t more companies take a page from Southwest’s efficiency? The cynical answer is, airlines don’t want your boarding experience to be easy or enjoyable; if it was, nobody would buy costly seat upgrades or pre-boarding plans. Of course, all of this would be moot if more airlines did away with their steep checked baggage fees, which force budget-minded travelers to schlep bulky carry-on onto the plane with them, clogging up the overheads and the aisles with their overstuffed roller bags. Axing baggage fees could bring an immediate 27 percent reduction in carry-ons, by one estimate, which is good for everyone. When can we expect airlines to see the research-verified light?

When pigs fly.