ACI World urges regulators to overhaul outdated airport slot allocation framework as capacity crunch grows

Airports Council International (ACI) World has released a white paper calling for modernisation of the global airport slot allocation system, warning that an outdated framework designed more than 50 years ago is creating barriers to connectivity and competitiveness.

The trade association said the framework managing slot allocation has not kept pace with aviation’s growth. With the number of the world’s most congested, slot-restricted airports surging by more than 25 per cent over the last decade, and global passenger traffic projected to nearly double by the mid-2040s, ACI World is calling on regulators to engage with industry to modernise the system before the capacity crunch escalates further.

Justin Erbacci, Director General of ACI World, said: “We are trying to run a 2026 aviation industry on a 1970s operating system. Airports are doing their best to operate within an outdated regulatory framework, but the reality is that these inflexible rules and practices are preventing the industry from adapting to modern passenger demands… ACI World urges regulators to sit down with the industry and finally deliver the overdue upgrade that our passengers deserve.”

The white paper, titled Airport Slot Policy – Rethinking Airport Access in a Capacity-Constrained World, outlines how the current system affects stakeholders across the aviation ecosystem. Fewer than 10 per cent of the world’s airports handle nearly two-thirds of all passengers, and 85.5 per cent of the busiest, those serving more than 40 million passengers a year, are already operating at or near full capacity. ACI World said today’s system offers little visibility into how decisions about scarce capacity are made, and called for greater transparency around who is requesting access, who receives it and why.

The paper also argues that the current system limits competition and consumer choice. At the 50 most congested airports, the four largest airlines account for 67 per cent of flights, with historic access rights accumulating over time and rarely released. ACI World said existing guidelines heavily prioritise historical allocation and incumbent airlines, making it difficult for the system to adapt as demand changes, and argued that defending the status quo poses a greater risk to stability than reform.

Erbacci added: “Airports are ready to do the work, but we cannot build the future of aviation alone. We strongly urge airline representatives and legacy industry bodies to move past historical resistance and a ‘zero-sum’ mentality and join us in improving the slot allocation system… it is time to design a transparent, future-ready framework that unlocks operational efficiency and fosters healthy competition.”

Read more information here.