Passengers stand in line waiting to board a flight at John F. Kennedy Airport. Photo: Chip Somodevilla/Getty Images

On a recent Delta flight, I discovered I had been demoted.

Until this January, Delta boarding included a “Sky Priority” phase that put frequent flyers in the two middle tiers (“Platinum Medallion” and “Gold Medallion”) of Delta’s four-tier elite flyer program together with passengers sitting in extra-legroom “Comfort+” seats at the front of the coach cabin. But, since January, the Comfort+ passengers have been allowed to go before the mid-tier Medallion passengers like me, which means I often have to board later than I was used to.

Rough, right?

Of course, it wasn’t always this complicated. I am an old millennial, old enough to remember that airplanes used to be boarded from back to front. People needing special assistance and first class got to board first, but after that, you filed in based on your row number. That’s all changed, for two reasons, both of which can be thought of as technological advancements of sorts.

One thing that happened was that airlines discovered that boarding by row in reverse numerical order, while intuitive, is one of the slowest possible ways to board an airplane, because people bunch up trying to use the same bins and squeeze into the same rows at once. Even boarding in a random order is about 30 percent faster than boarding the old-fashioned way.

But there’s no need to be strictly random. If airlines don’t need to board back to front, they might as well hand out early boarding in a way that helps them make more money. As I’ll discuss below, they have increasingly settled on a boarding order driven by social stratification, but if you look back at the coverage of the first wave of boarding changes, airlines were focused on a different imperative: finding the fastest possible boarding method, so planes can spend less time at gates and more time in the air, making money.

They might have stuck with that aim if it weren’t for the other change, which has to do with the fight for overhead bin space. The size of these bins has become insufficient for a few reasons. The first was that luggage makers rolled out (see what I did there?) much more maneuverable mid-size suitcases that could fit in an overhead bin. These better suitcases, combined with airlines’ introduction of checked bag fees, led travelers to start carrying more luggage on board the plane. Airline consolidation, a strong economy, and lessons learned from past bankruptcies have led to restrained growth in airline capacity and fuller aircraft, with fewer seats (and less bin space) to spare.

These effects have combined to mean passengers try to bring more luggage on board planes than can actually fit in the overhead bins and underneath seats, which means late-boarding passengers are at risk of having their bags gate-checked, thus imposing the dreaded wait at the baggage claim to retrieve a bag. (I will never forget the look my then-boss gave me at the Tampa airport on my very first business trip, when she briefly came under the mistaken impression that I had checked a suitcase and we would have to wait for it at baggage claim.) Because of this competition for scarce luggage storage space, passengers are not indifferent about when they board the plane, and place a high value on being allowed to board first.

So, airlines have begun slicing the boarding order more and more thinly, boarding customers approximately in the order of their value to the airline: First the premium cabins, then those customers who paid extra for better seats in the main cabin, then customers who fly the airline a lot, then customers who fly the airline pretty often, then normal people, and finally people who bought “basic economy” tickets that come with a bargain price in exchange for a willingness to be degraded. In order to apply these fine distinctions, United boards in six groups, while American and Delta each have ten.

In recent years, American and Delta have had to rename their boarding groups to fix an absurdity: American had a “Group 1” and Delta had a “Zone 1,” but these groups did not in fact board first, but were behind various more-privileged boarding groups, from first-class passengers to high-frequency flyers to those who had purchased extra-legroom seats. Often, “Zone 1” meant about half the passengers on the plane got to board before you, which doesn’t feel very number one at all.

So, American gave all its boarding groups numbers, even the premium ones, and “Group 1” became “Group 5.” Citibank had to send an email to American co-brand cardholders telling them they’d now be boarding in “Group 5,” but that this wasn’t a demotion because they’d really been in the fifth group all along. Actually, “Group 5” is the sixth group — American still allows its most elite Concierge Key fliers to board before “Group 1,” as a sort of Group 0 — but who’s counting? (Just kidding: These people are definitely counting.)

Delta added a qualifier to its numbers, renaming “Zone 1” to “Main Cabin 1,” emphasizing that passengers in it are first among a specific kind of ticketholder but not first overall. But even that name still isn’t quite accurate: Elite flyers at the Gold Medallion level and higher board ahead of Main Cabin 1, even if they are in fact sitting in the main cabin.

Darren Murph, who covers Delta for The Points Guy, writes that “Delta’s dogged collection of passenger and employee feedback has shown that people prefer boarding in groups that feel more exclusive.” I suspect there was another factor behind the decision to break boarding into even more groups: that Medallion passengers were ignoring the “Reserved for Comfort+ Passengers” signage inside the overhead bins, and sticking their huge bags in bins over Comfort+ rows before stepping back to their actual seats farther back in the main cabin. Letting Comfort+ board first increases the odds these passengers will get the premium bin space they paid for.

All of this ultrastratification is kind of annoying. But I think it is possible that we won’t need super-thin-sliced boarding forever, or at least we won’t need to care about it very much, because of some additional technological advances that are working their way into the air travel system that could make boarding order as unimportant as it once was.

One is bigger overhead bins that have room for all the crap we carry on board now. Delta has installed these on much of its fleet — suitcases fit sideways, so more can fit in each bin, and more can fit on the plane overall.

Baggage handling also seems to be getting better. Maybe this is a consequence of the practice of charging for checked bags: Airlines need to show customers they’re getting value for what they paid. Delta even allows me to track my bag from my phone and guarantees delivery to the baggage claim within 20 minutes of arrival, or else I get extra frequent flyer miles. I now find that when I check a bag, it often gets to the baggage claim before I do.

Bag fees of course are still a disincentive to check luggage, but — as you can see from all the passengers lining up to board in the earliest groups — many flyers are eligible to check a bag for free because of their airline status, or their ticket type, or what credit card they carry, and so making luggage check less of a pain could encourage a lot more customers to use it.

All of which is to say, we may have a future where overhead bin space is no longer scarce, and customers can be reasonably sure they’ll have a spot for the bag they brought — and also reasonably indifferent to the possibility that a gate agent might seize the bag and put it in the hold.

But for now, I am adopting a different strategy.

Instead of a roll-aboard suitcase, I’ve started using a soft-sided duffel bag, along with a backpack, for trips of five days or less. Since much of the weight of a rolling suitcase is the suitcase, the duffel is surprisingly lightweight. I can sling it over my back and Citibike to Penn Station with it instead of walking or taking a car. I’m pretty sure I’ll be able to talk a gate agent into letting me carry it on, even if I’m boarding late. And if I am forced to check it, it will probably get to the baggage claim reasonably fast.

With this approach, I don’t have to sweat the boarding order too much, crowd the gatehouse, or worry that I’ll get demoted again. I can even sit back and board last.