Written by Juan Carlos Machorro, Andres Remis, and Emilio Nicanor Gaytán López

On 28 October, 2025, the U.S. Department of Transportation (DOT) imposed unprecedented restrictions on Mexican aviation. The DOT blocked Mexican airline routes, froze future growth from both Mexico City airports (AICM and NLU), and proposed banning cargo on passenger flights between AICM and the United States. The reason: Mexico’s violations of the 2015 bilateral aviation agreement. While legitimate concerns exist about Mexican government policies, the legal case presents both strengths and weaknesses.

What Did the DOT Actually Do?

The sanctions came in two parts. First, schedule disapprovals affecting Aeroméxico, Volaris, and VivaAerobus: immediate cancellation of Aeroméxico’s NLU-Houston and NLU-McAllen flights; blocking new routes like Aeroméxico’s AICM-San Juan and Volaris’s AICM-Newark; and a complete freeze on future route applications from either Mexico City airport to any U.S. destination.

Second, the DOT proposed banning Mexican airlines from carrying belly cargo on passenger flights, between AICM and the United States, effective approximately five months after finalization. These represent some of the most severe unilateral actions taken against any aviation treaty partner in modern history.

What Is Mexico Accused Of?

1. Banning Cargo-Only Flights from AICM

In February 2023, Mexico prohibited dedicated cargo airlines from operating at AICM, forcing carriers like FedEx, UPS, and Atlas Air to relocate to NLU (40 kilometers away). However, passenger airlines can still transport cargo in their lower deck at AICM. This violates Mexico’s treaty obligation to allow U.S. all-cargo services to “any point in Mexico” and creates fundamentally unfair competition: passenger airlines operate from centrally located AICM with superior domestic connectivity, while cargo carriers operate from a remote airport with limited infrastructure and connectivity.

2. Confiscating Landing Slots

Beginning in August 2022, Mexican authorities reduced AICM’s hourly capacity from 61 to 52, then to 43 operations. While both Mexican and U.S. carriers lost slots, Mexican carriers subsequently added numerous new U.S. routes by “repurposing” remaining slots while U.S. carriers remain frozen. The DOT also criticizes Mexico’s slot allocation system as opaque, non-transparent, and operated without adherence to international standards (WASG).

3. Canceling NAIM

The DOT explicitly references the 2018 cancellation of the Nuevo Aeropuerto Internacional de México (NAIM), stating Mexico “destroyed a partially constructed new airport that would have provided ample capacity.” This represents a formal characterization of a sovereign infrastructure decision as part of a pattern demonstrating systematic disregard for treaty commitments.

Do These Arguments Hold Up?

The Cargo Ban: DOT’s Strongest Case

This represents the clearest violation. The bilateral agreement unambiguously grants U.S. carriers rights to operate all-cargo services to any point in Mexico. A categorical ban at AICM appears directly inconsistent with that right.

Mexico argues the ban applies equally to all cargo operators regardless of nationality. However, this “equal treatment” argument seems inadequate when Mexican combination carriers, primarily Aeroméxico, enjoy full AICM access for belly cargo while U.S. all-cargo competitors are banished to a remote airport. Mexico also invokes capacity management authority, but has provided no technical analysis justifying why dedicated cargo operations must be prohibited while combination operations carrying cargo can continue. The decree appears driven by political objectives rather than operational necessity.

The Slot Confiscations: Weaker Legal Ground

This allegation presents complex terrain. The bilateral agreement contains no slot allocation provisions, aviation treaties typically don’t regulate how airports allocate landing times. Moreover, Mexican carriers also lost slots alongside U.S. carriers, suggesting non-discriminatory application.

However, the DOT identifies legitimate concerns about Mexico’s slot system. Mexican procedures lack transparency and deviate from WASG standards, creating opportunities for arbitrary decisions. While proving specific discrimination is difficult, the opacity is problematic. Mexico’s October 2025 updated guidelines move somewhat closer to international standards, but maintain concerning elements: the coordinator lacks genuine independence, transparency remains incomplete, and sufficient discretion persists for arbitrary allocation. Critically, Mexico has committed to returning confiscated U.S. slots, but as of late 2025, these commitments remain unfulfilled, a pattern reinforcing DOT concerns about Mexican government follow-through.

NAIM Cancellation: Sovereignty with Consequences

The DOT’s position, that canceling airport construction can contribute to treaty violations, raises sovereignty concerns. International law recognizes broad authority over infrastructure decisions. Countries rarely face treaty obligations to complete particular projects. However, dismissing NAIM as mere background misses its critical importance.

NAIM was designed to relieve AICM’s chronic capacity constraints. U.S. carriers reasonably relied on its completion based on years of governmental commitments and substantial construction progress. The cancellation triggered a chain reaction: AICM remained severely constrained, then Mexico prohibited all-cargo operations entirely from AICM, creating substantial logistical bottlenecks that persist today.

The current configuration forces operational inefficiency. All-cargo carriers operate from NLU, while combination carriers continue at AICM with seamless domestic connections. Cargo arriving at NLU must be transported by land to AICM for onward distribution, adding significant time, cost, and complexity. Meanwhile, combination carriers move cargo seamlessly without any airport transfer, providing substantial structural competitive advantage. U.S. all-cargo carriers bear the full burden of these disadvantages.

The legal question: Did canceling NAIM, maintaining AICM capacity constraints, and then prohibiting cargo operations while exempting passenger operations goes from legitimate sovereign choice beyond denying U.S. carriers’ treaty rights? The DOT says yes; Mexico argues legitimate policy within sovereign authority. The DOT’s concerns about cumulative competitive impact are difficult to dismiss entirely.

Competition, Timing, and Proportionality

The Delta-Aeroméxico joint venture context matters. Since 2016, these airlines have operated an antitrust-immunized partnership. The DOT notes their AICM market share increased from 50% (2016) to 60% (2024), handling 73% of cargo tonnage. While the DOT properly revoked their antitrust immunity in September 2025, using treaty enforcement for additional sanctions risks weaponizing international law for domestic competition battles. However, this shouldn’t obscure the legitimate underlying concern: Mexican policies create structural advantages for combination carriers (primarily Aeroméxico) over all-cargo operators (primarily U.S. carriers).

The escalating U.S. actions, including schedule filing requirements (July 2025), immunity revocation (September 2025), and comprehensive sanctions (October 2025) suggest coordinated strategy. Mexico’s October 2025 slot guidelines and slot return commitments represent effort toward reform, but concrete implementation remains absent. Mexico has a track record of commitments without follow-through, fueling DOT skepticism.

On proportionality, the sanctions present mixed results. If the violation is the cargo ban, why block passenger routes? If it’s slot allocation at AICM, why restrict NLU services where no violations are alleged? The proposed cargo prohibition escalates beyond Mexico’s measure as it would ban all cargo on passenger flights, whereas Mexico’s decree only prohibits dedicated cargo operations. The 108-business-day deadline constitutes an ultimatum seemingly designed to ensure non-compliance rather than facilitate resolution. However, given Mexico’s pattern of unfulfilled commitments, the DOT’s firm deadlines appear pragmatically justified despite legal concerns.

Dispute Resolution and Precedent

The bilateral agreement incorporates formal dispute resolution procedures. The DOT references consultations with Mexican officials but provides no indication that formal treaty mechanisms were exhausted before imposing sanctions. This unilateralism creates problematic precedent, if the U.S. can unilaterally determine violations and impose sanctions without neutral review, any country with sufficient leverage could employ similar tactics.

However, Mexico has shown limited interest in genuinely addressing concerns through diplomatic channels. Consultations yielded commitments without implementation. From the DOT’s perspective, further negotiations without enforcement leverage may simply enable continued delay. The decision to impose sanctions before exhausting formal dispute resolution, while procedurally questionable, may reflect pragmatic recognition that Mexico responds to pressure rather than dialogue. A neutral arbitration panel could still provide authoritative treaty interpretation and recommend remedies both countries could accept.

What This Means and What Happens Next

This dispute raises fundamental questions about aviation treaty reach into domestic policy. Can countries face sanctions for infrastructure decisions affecting carrier expectations? Can they prioritize passenger service over cargo operations at congested airports? The DOT’s positions are expansive and precedent-setting, potentially transforming aviation treaties from guarantors of non-discriminatory access into constraints on core governmental functions. However, Mexico’s pattern, canceling infrastructure, imposing categorical bans, maintaining opaque systems, provides substantial support for DOT concerns about systematic denial of U.S. carrier opportunities.

While schedule disapprovals are in effect, the cargo prohibition remains tentative, subject to comment periods before taking effect 108 business days after finalization. Mexico could retaliate, seek arbitration, or pursue court appeals. The most productive path involves negotiations producing verifiable solutions: genuinely transparent slot allocation with independent oversight, meaningful new entrant access, and phased cargo compromise. However, this requires Mexican government willingness for substantive changes rather than cosmetic reforms. The track record suggests skepticism is warranted, though sanction severity may compel meaningful action.

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