On August 20, 2026, the 11th Circuit Court of Appeals vacated the DOT order that would have ended the Delta-Aeromexico joint venture, keeping the partnership’s antitrust immunity intact. For travelers, this preserves through-checked baggage on connecting Delta and Aeromexico itineraries, reciprocal elite bag benefits, and coordinated fares across US-Mexico routes.

If you fly between the US and Mexico, a courtroom in Atlanta just protected something you probably never think about until your suitcase is on the line. The 11th Circuit Court of Appeals overturned a government order that threatened to unwind the Delta-Aeromexico partnership. That partnership does more than coordinate schedules and prices. It quietly shapes how your checked bag moves from Detroit to Guadalajara without you touching it in between.

Here’s what the ruling actually says, and more importantly, what it means for your luggage on your next trip.

What Did the Court Actually Decide?

The 11th Circuit ruled on August 20, 2026, that the Department of Transportation acted “arbitrary and capricious” when it revoked the Delta-Aeromexico antitrust immunity in September 2025. The court vacated that order, allowing the joint venture and its passenger benefits to continue.

In the case Delta Air Lines, Inc. and Aerovias de Mexico, S.A. de C.V. v. U.S. Department of Transportation, Judge Elizabeth Branch wrote that the DOT “did not reasonably explain why it conducted a far more limited market analysis in this case than it has always done in the past.”

The court flagged two problems with the DOT’s reasoning:

• Narrow analysis: When the DOT approved the joint venture in 2016, it studied 1,687 city-pair markets. When it tried to kill the venture nine years later, it leaned almost entirely on conditions at Mexico City’s Benito Juárez International Airport (MEX), skipping the broader country-level and city-pair review.
• Inconsistent standards: The DOT made Open Skies compliance a requirement for the Mexico partnership, yet approved two similar joint ventures in Japan despite restrictions at Tokyo’s Haneda airport.

The DOT said it is reviewing the decision and weighing its legal options. So this may not be the last word but for now, the partnership stands.

Why Does This Partnership Matter to Everyday Flyers?

The Delta-Aeromexico partnership, launched in 2017, lets the two carriers coordinate scheduling, pricing, and revenue sharing across US-Mexico routes. Delta also holds a 20% stake in Aeromexico. Together, they operate as a “metal-neutral” joint venture, meaning it doesn’t matter which airline’s plane you board the two act like one carrier on these routes.

That single-carrier behavior is exactly what makes your baggage experience smoother. Consider the market weight behind it. In August 2026, the combined partnership offered 731,335 scheduled seats between the two countries.

Had the venture dissolved, the two airlines would have operated more like distant partners than a single team and that would have directly affected how far your bag travels on one tag.

How Does Through-Checked Baggage Work on Delta-Aeromexico Flights?

Through-checked baggage means your bag is tagged at your first airport and travels all the way to your final destination without you re-claiming it at a connection. On Delta-Aeromexico itineraries, this benefit applies even when you have two separate tickets a rare exception most airline pairs don’t offer.

Here’s why this is a big deal. Delta’s standard rule is simple: on a single ticket, it checks your bag from origin to destination. On separate tickets, you’d normally have to grab your bag at the connecting airport and re-check it yourself.

But Delta lists Aeromexico among a short group of partners it will still through-check bags for, even on separate tickets. The full list includes:

• Aeromexico
• Air France
• China Eastern
• KLM
• Korean Air
• LATAM
• Virgin Atlantic
• WestJet

Real-world example: You fly Delta from Atlanta (ATL) to Mexico City (MEX), then connect on an Aeromexico-operated flight to Mérida. Thanks to the partnership, your suitcase is checked straight through to Mérida. You clear customs at MEX, drop your bag at the recheck belt, and it continues on no dragging it through the terminal to a separate counter.

If the joint venture had ended, this separate-ticket through-check exception was one of the first conveniences at risk.

Delta-Aeromexico Codeshare Baggage: Whose Rules Apply?

On a codeshare flight, the marketing carrier’s baggage rules generally apply not the operating carrier’s. This means if you booked a Delta-numbered flight actually flown by Aeromexico, Delta’s baggage allowance and fees typically govern your bag, per US Department of Transportation guidance.

This trips up a lot of travelers, so let’s make it concrete.

• Marketing carrier = the airline whose code and flight number appear on your ticket.
• Operating carrier = the airline whose plane you actually fly.

Example: Your ticket says “Delta DL 8xxx,” but you board an Aeromexico jet. Delta is the marketing carrier, so Delta’s baggage rules apply. The reverse is also true an Aeromexico-marketed flight flown by Delta follows Aeromexico’s rules.

Why does this matter? The two airlines treat carry-ons very differently:

So if your itinerary is marketed by Aeromexico, that heavy carry-on you’d sail through on a US Delta flight could get weighed and sent to the hold for a fee. Always check your booking confirmation to see which carrier’s code sits on your ticket.

Delta-Aeromexico Checked Baggage Allowance by Cabin

Your free checked baggage allowance depends on your fare class and which carrier’s rules apply. On Aeromexico’s own fares, Basic (Básica) tickets include no free checked bag, Classic and AM Plus include one, and Clase Premier includes two to three. On Delta-marketed tickets, standard Delta allowances apply.

Aeromexico fare allowances:

On Delta-marketed US-Mexico flights, economy fares generally include no free checked bag, while Delta One and First class include two free bags up to 70 lbs each.

Elite status is where the partnership shines. Delta Medallion members receive free checked bags that extend to some partner-operated flights. Silver Medallion members get one free bag, Gold members get two, and Platinum and Diamond members get three. Because Delta and Aeromexico share SkyTeam elite recognition, your status is honored across the partnership another benefit that leaned on the joint venture staying alive.

Delta-Aeromexico Baggage Fees: The Full Breakdown

For US-Mexico routes where a bag isn’t included, expect to pay $45 for your first checked bag each way on Delta-marketed flights. Fees climb quickly for additional, overweight, or oversized bags, and they apply per direction so double them for a round trip.

Delta baggage fees on US-Mexico routes (each way):

Cost scenario: A family of three flying Atlanta to Cancún round trip, each checking one bag, would pay roughly $45 × 3 bags × 2 directions = $270 in bag fees alone. Add one overweight suitcase at 55 lbs, and that’s another $100 each way $200 more.

How to cut that bill:

• Pre-pay online through Manage Your Trip at least 24 hours ahead Aeromexico’s airport counter prices run higher.
• Carry a Delta SkyMiles co-branded credit card (Gold, Platinum, or Reserve) for a free checked bag on Delta-operated flights though this perk does not extend to partner-operated segments like Aeromexico.
• Fly up front or earn Medallion status to unlock free bags that travel across the partnership.

Frequently asked questions

Does the court ruling change my baggage fees right now?

No. The August 20, 2026 ruling preserves the existing partnership, so baggage fees, allowances, and through-check benefits continue as they were. Nothing about your bag policy changes because of the decision it simply prevents the disruption that ending the joint venture would have caused.

Whose baggage rules apply on a Delta-Aeromexico codeshare?

The marketing carrier’s rules apply. If your ticket shows a Delta flight number, Delta’s baggage allowance and fees govern your bag even if Aeromexico operates the plane. Check the flight code on your confirmation to know which policy controls your specific trip.

Will my bag be through-checked if I have two separate tickets?

Yes, in most cases. Delta lists Aeromexico as an exception partner, meaning it will through-check your bag from origin to destination even on separate tickets. Confirm at check-in, since documentation and connection times still apply at your transfer airport.

How much is a first checked bag on a US-Mexico flight?

On Delta-marketed flights, the first checked bag costs $45 USD each way. On Aeromexico’s own fares, Básica includes none (pay to add), while Classic and AM Plus include one free bag. Clase Premier includes two to three free bags.

Does Aeromexico really weigh carry-on bags?

Yes. Aeromexico enforces a strict 10 kg (22 lbs) combined limit for your carry-on and personal item in economy, and gate agents actively weigh bags. Delta, by contrast, sets no carry-on weight limit so an Aeromexico-marketed flight is stricter here.

Do Delta Medallion benefits work on Aeromexico flights?

Yes. Delta Medallion status is recognized across the SkyTeam partnership, extending free checked bag benefits to Aeromexico-operated segments. Silver gets one bag, Gold two, and Platinum or Diamond three. This reciprocal recognition depends on the partnership remaining active.

Does my Delta credit card give me a free bag on Aeromexico?

No. Delta SkyMiles co-branded credit cards provide a free checked bag only on Delta-operated flights. Partner-operated segments, including Aeromexico, are not covered. If your bag benefit matters, rely on Medallion status instead for partner flights.

What is the checked bag weight limit on these flights?

Delta caps standard checked bags at 50 lbs. Aeromexico allows 23 kg (about 51 lbs) on international routes and 25 kg (55 lbs) domestically for Classic and AM Plus fares, and up to 32 kg (70 lbs) in Clase Premier. Overweight fees apply above these limits.

How can I avoid the highest baggage fees?

Pre-pay bags online at least 24 hours before departure, pack within weight limits, and use Medallion status or a premium cabin for free bags. Weigh your carry-on at home if flying an Aeromexico-marketed ticket, since gate weigh-ins can push it to the paid hold.

What would have happened to my bags if the joint venture ended?

Losing the joint venture likely would have ended the separate-ticket through-check exception and could have weakened reciprocal elite bag benefits. You’d risk re-claiming and re-checking bags at your connection and paying more, since the airlines would coordinate less closely.