It’s time for another Ask Cranky question.
After getting sick of being hassled on past trips for my stuffed carry-on bag, never mind that it always fit, wheels toward the windows, in the actual bins on [United], I bought a new, carry-on bag with stiffer sides. Yesterday, I took it to [Orange County airport] to try out the carry-on sizers for six airlines. Each claims the same dimensions. Five of the six airlines’ sizers gave me no problems. I tried not one, but two sizers for Alaska Airlines. In each, I had to struggle to shove this bag into that sizer. It’s almost as if Alaska is intentionally shorting the size of its sizers to force bag charges. I smell fraud, and it certainly makes me less inclined to fly Alaska. What do you think?
Doug

This was quite the mystery, and I was pretty curious myself. Doug sent me photos of him putting his bag in sizers from Alaska, American, Delta, and United. Each of those airlines advertises a maximum carry-on dimension of 9″ x 14″ x 22″ so the bag should fit the same in each, right? Wrong.
First, I had to track down the bag itself to get dimensions. This is a Delsey bag from Costco which according to the website is actually 9.5″ depth x 15″ width x 22.6″ length including the wheels and handle. Why Delsey has decided to make a bag that actually exceeds the limits allowed by airlines is unclear to me. But this makes me think that Alaska is just enforcing its rules more tightly and not actually making the sizer smaller than advertised. Other airlines are just more generous.
This quickly turned into an evaluation of bag-sizer design. Yes, I went down quite the rabbit hole. Let’s start with United.

As you can see, United only has physical barriers on the depth and for half the width (the top is open), though obviously there is some buffer on both since it shouldn’t have fit if the sizer was rigidly adhering to the limits. For length, it leaves it wide open on both sides. The permitted length is shown on the diagram, but it looks like the wheels might have stuck out a bit had there been physical barriers on those sides. Since there weren’t, it fit.
Next, let’s move on to American.

American also has physical limits on depth and half of width, but unlike United it has barriers on length as well. As you can see, however, the barriers are low and have gaps that appear to allow for wheels to stick out. This too is more lenient.
And now, Delta.

Delta has bigger physical barriers on all sides except the top, but they appear to be designed with a lot more room than the rules would indicate. This is the most generous one so far.
Lastly, let’s look at Alaska.

In this one, the length and depth are fully locked in and appear to be at the exact dimensions permitted by the airline. For that reason, the bag doesn’t fit. And if it doesn’t fit, you must acquit… or something like that.
So is this fraud? I didn’t take a tape measure out, but I don’t think so. It looks like Alaska is just sticking strictly to the dimensions while the others give a buffer. That’s frustrating for someone who regularly carries on a bag and then flies Alaska for the first time only to be denied. (In this case, Doug was allowed to board, so at least there’s there.) If you’re flying Alaska, be careful.
It would be nice if airlines could be consistent.