México has long done things its own way when it comes to aviation, sometimes without rhyme or reason. That is what has gotten the country into trouble with the US recently thanks to claimed violations of aviation agreements. Now with the US ratcheting up pressure, the country appears to be backing down.

Most of this dispute centers around the highly-constrained Mexico City airport (MEX). The country was well along in building a massive new airport to relieve congestion, but when Andrés Manuel López Obrador took over as president in 2018, he ended that plan entirely. Instead, the Santa Lucia military base was turned into AIFA, a reliever airport that is increasingly dominated by Viva. MEX remained very tightly constrained.

AIFA by itself wasn’t a great plan, but it didn’t get under the US’s skin. It’s what happened afterwards to further restrict MEX that ruffled feathers.

México arbitrarily decided that all MEX cargo operations would have to move to AIFA. Airlines may have had their slots, but that didn’t matter. They all had to move. As you can imagine, some very prominent US cargo carriers were none-too-pleased.

Then in the summer of 2022, the adminstration decided that MEX’s capacity needed to be slashed. Ch-aviation notes that hourly slots went from 61 to 44 starting in the winter 2022/2023 schedule and into the next summer. It was vaguely related to some planned construction, but that never happened, and the limits were never brought back up.

These two primary issues came together to make the parties rather unhappy. In July, the US decided it was done messing around. It put out a couple of rules that just added paperwork and pain, but the biggest issue is that the country threatened to end the joint venture between the Delta and Aeromexico. Though not stated, presumably this also means that the long-proposed Allegiant/Viva joint venture would never be approved either.

You would think México wouldn’t care all that much what the US did, but clearly Aeromexico has some friends in powerful places that have convinced the country to make some changes.

Now, México is reportedly going to restore slots. Details aren’t entirely clear at this point, but of course the big beneficiaries would be the Mexican carriers that have lost far more than US carriers. But US carriers will benefit… at least three of them will.

Alaska, JetBlue, and Southwest all tried and failed to make Mexico City work. They pulled out before the pandemic, so it’s just the big three US carriers that remain.

I tried to figure out exactly how many slots went away and what might be restored, but it’s not actually that simple. Let’s take a look at each of the three, in alphabetical order, starting with American which has given me the most clarity.

American Average Daily Departures to Mexico City

^{Data via Cirium}

American has had a steady state of 14 daily in winter and 13 daily in summer. A spokesperson explained that there is a weird partial slot that operated in the first quarter of the year, but that has been handed back and LAX has been suspended during that time period.

American had to cut back two daily flights when it lost slots, though this past winter (and next winter as well) saw it add one Phoenix flight that operated late night/early morning and was unrelated to the steady-state slot count. Next winter, American is getting a slot back which it will use to start Chicago/O’Hare.

I’m told that this is just for winter at this point. The summer slot process for next year has not completed, but there is hope that American will be back up at 13 again then with the number of slots it had before being cut down. We shall see when slots get awarded.

Delta Average Daily Departures to Mexico City

^{Data via Cirium}

This one, I don’t think really matters. Since Delta and Aeromexico are joint venture partners, it looks like Delta has been able to find a way to restore what it had before.

Delta was at 10 before the cuts, but then again, the cuts didn’t take place until after summer 2022 and Delta was already down at eight then. Then it was back at 10 again by summer 2024. And now this coming winter it has suspended LAX itself, so it’s lower again.

To me, this one is worth ignoring since I just don’t know how the Aeromexico relationship fits into all of this.

United Average Daily Departures to Mexico City

^{Data via Cirium}

Then there’s United, and I’m completely at a loss. Maybe it lost one slot? But it has been back up, reaching new heights in winter. Perhaps there are fewer slots being used in winter, so United can temporarily get them. Or it’s possible that United is doing that late night/early morning flying like American to skirt around slots. Regardless, it seems like United has been the least impacted based purely on frequency.

United did just recently file plans to fly from Denver next winter as a new route, apparently replacing one of the O’Hare frequencies. But maybe it won’t have to cut O’Hare if it gets a slot or two back.

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I’ll be honest, I don’t really get this fight. Sure, México is absolutely playing weird games. There are shenanigans here, but this isn’t targeting the US directly. It’s a broader move… a dumb one, yes, but not one targeting the US. Still, the US is unhappy, and it likely does count as a violation of the open skies agreement, so it will continue to push. And México appears to be bending.