Airlines vs. Airports: Debate Over Slot Regulation and Capacity Intensifies

The International Air Transport Association (IATA) and Airports Council International (ACI) are locked in a debate over airport capacity and slot regulations — defined as the designated times at which airlines are permitted to land or take off at airports — with both sides offering differing views on how to address the challenges posed by rising air traffic demand.

IATA’s case for accountability and efficiency

IATA recently released a White Paper highlighting the growing airport capacity crunch and proposing reforms to slot regulations.

The association highlighted the need for airports to maximize the use of existing infrastructure, citing that nearly 400 airports globally already require slot coordination under the Worldwide Airport Slot Guidelines (WASG), a number expected to grow by 25 percent in the next decade.

“The only cure for insufficient capacity is construction,” said Nick Careen, IATA’s Senior Vice President for Operations, Safety, and Security, stressing the urgency of the issue. “But as long as large-scale projects remain politically out of reach, we must squeeze every last unit of capacity out of the infrastructure we have.”

IATA’s White Paper advocates for stronger obligations on airports to increase transparency, regularly review capacity declarations, and face consequences for failing to deliver promised capacity.

According to Careen, the existing imbalance in slot regulation “unfairly places” all performance obligations on airlines.

“Airports face no penalties if they don’t deliver promised capacity,” he said. “This needs a major rebalancing so that airports and airlines are equally obliged to maximize the potential social and economic value of airport capacity.”

ACI’s call for collaboration

ACI World and ACI Europe swiftly responded, rejecting IATA’s assertions and proposing a more collaborative approach to solving the capacity challenge.

Darryl Dowd, Vice President for Safety, Security, and Operations at ACI World, highlighted the complexity of optimizing airport capacity, pointing to the role of various stakeholders beyond airports: “The delivery of airport capacity depends on coordinated actions from air traffic management, regulators, and other stakeholders. Airports alone cannot solve this multifaceted challenge.”

ACI World also criticized IATA’s focus on holding airports solely accountable, arguing that airline practices, such as inefficient slot use and resistance to “reasonable” airport charges, also hinder capacity optimization.

ACI Europe: Airlines must share responsibility

ACI Europe’s response was even more pointed, highlighting the “outdated” EU Airport Slot Regulation as a barrier to competitive and efficient capacity use.

The association accused IATA of deflecting blame onto airports while “ignoring” airlines’ role in capacity wastage.

“IATA’s assumption that many airports are not doing enough to squeeze more capacity out of their existing infrastructure is ludicrous,” Olivier Jankovec, Director General of ACI Europe, said. “Airlines should focus on improving their slot usage — returning unused slots more quickly and refraining from hoarding them.”

Jankovec stressed that modernizing slot regulations is essential for Europe’s competitiveness and connectivity:
“The undue pressure on airports to make promises on capacity that cannot be fulfilled due to physical constraints is yet another attempt by IATA to defend the status quo.”

A shared problem, Divergent solutions

While both sides agree on the urgent need to address the airport capacity crunch, their solutions diverge sharply. IATA insists on stronger regulation to hold airports accountable, while ACI advocates for a collaborative approach that includes reforming slot regulations and addressing airline inefficiencies.

As air traffic demand continues to grow, the debate underscores the challenges of balancing infrastructure limitations, economic pressures, and regulatory frameworks. Bridging this divide will require not just policy changes but also a willingness from both parties to work together for the benefit of passengers and the aviation ecosystem.