UK relaxes airport slot rules as IATA calls for other countries to follow suit
April 27, 2026
With the threat of aviation fuel supplies potentially running short, airlines have begun taking remedial action to reduce usage and conserve stocks. This has so far primarily taken the form of flight cancellations and frequency reductions.
Yet, with flight cancellations comes a risk that ‘use-it-or-lose-it’ slot rules could be broken as airlines fail to meet mandated usage levels for some of the world’s most congested airports.
Now, with IATA calling for special dispensation for airlines should usage fall below the required level, the UK has become the first country to provide some concrete guidance on this issue.
The UK relaxes airport slot usage rules to protect airlines
With the closure of the Strait of Hormuz now in its eighth week, international concern is growing about the global stocks of aviation fuel and whether supplies could run dry over the peak summer period.
Europe is particularly affected by this blockade since the continent imports around 30% of its jet fuel requirements, and the majority of these imports come via the Strait of Hormuz.
With some airlines making cuts to their summer flying programmes, ostensibly to conserve fuel usage, governments and industry bodies are turning their attention to the issue, primarily to alleviate the growing fears of the travelling public.
However, there is also growing concern among airlines that they could be penalised should they fail to use slots at airports due to possible fuel shortages impacting the industry.
On 24 April, the UK government updated its guidance to airlines on the use of landing and take-off slots at some of the UK’s most important airports. These slots are a valuable commodity at airports where demand for these slots outweighs the supply.
What is an airport slot and why are airlines worried?
A slot is an allocated period of time (normally around five minutes) in which an aircraft must land or take off from that airport, which helps the airport operator to plan and regulate movements during any 24 hours.
Slots are allocated following an application process by the airlines, and are usually allocated on a seasonal basis, based on the published International Air Transport Association spring/summer and autumn/winter scheduling seasons.
Under normal slot usage rules, airlines must use at least 80% of their allocated slots during a season to keep them for the following year (known as ‘grandfather rights’). If they fall below this threshold, those slots can be reassigned to another airline.
This is known as the ‘use it or lose it’ rule, otherwise the ‘80/20’ rule, which ensures that valuable slots are not allocated but then left unused by airlines.
Airlines can apply for exemption from UK slot rules amid Iran fuel crisis
On 24 April, Airport Coordination Limited (ACL), the independent body that manages slot allocation at the major UK airports, updated its guidance so that airlines will not lose their slots if fuel shortages prevent them from flying.
Airlines can now apply for an exemption from the use it or lose it rule in these circumstances. This means airlines can focus on minimising disruption for passengers, rather than feeling pressure to operate flights purely to protect their slots.
Despite these arrangements being put in place, ACL is keen to stress that these are contingency plans, only to come into effect should airlines be forced to cancel flights due to fuel shortages. However, the UK government has also issued a statement confirming that there is no current jet fuel shortage in the UK and advised passengers not to change travel plans.
Moreover, UK airlines reportedly said they were not currently seeing supply shortages at the time of writing, and that they are running their schedules as planned, albeit with some minor alterations.
With ACL relaxing the usage rules for slots only under strict conditions, this has been designed to prevent airlines from cancelling services for purely economic or other spurious reasons, to ensure that the rights of passengers are protected throughout the busy summer peak season.
IATA is calling on other governments to relax slot usage rules
The move by ACL in the UK is the first indication that airport slot coordinators may be willing to relax their own use-it-or-lose-it rules, as the potential threat of fuel shortages grows.
According to a report published by the International Air Transport Association (IATA) on 14 April, there is a growing need for more airport authorities to take a similar approach so that airlines are not penalised for not being able to operate due to fuel shortages.
In its role as the airline industry’s spokesperson, IATA has historically been leading global policy on the usage of airport slots. In its role, IATA coordinates the Worldwide Airport Slot Guidelines (WASG), a set of guidelines and policies that govern how airport slots are allocated and used and prescribe sanctions when they are not.
The WASG regulations provide both the rules by which airport slots are allocated and, because the underuse of these vital assets would be wasteful, the WASG also provides the rules by which a slot can be reallocated. This is the basis of the 80/20 rule.
A slot must be used 80% of the time for an airline to keep it going forward. The 20% non-utilisation provides flexibility for cancellations for things like weather events or mechanical issues that are deemed to be beyond the airline’s control.
While IATA recognises that the 80/20 rule has its flaws, it says it generally works well in ensuring that slots remain utilised. However, the trade body also recognises that there are sometimes circumstances where slots remain underutilised, such as during the COVID-19 pandemic, where it would be inequitable to punish an airline should this be the case.
The IATA principles allow for the non-use of slots in certain circumstances
The WASG has provisions for these scenarios called the Justified Non-Use of Slots (JNUS) exemption. Essentially, the utilisation calculation is frozen until the extraordinary situation normalises, and airlines can reasonably be expected to operate their schedules.
According to IATA, the conflict in the Middle East and potentially the supplies of aviation fuel running short are situations where JNUS needs to be applied.
Over the last month, with airspace closures, reduced operations at some airports, and major re-routing to avoid conflict zones, it has been impossible for many airlines to operate their planned schedules. This has caused increased anxiety, which is being exacerbated by the risk of fuel supplies running short.
As a result, through IATA, airlines are asking for governments to apply JNUS for a rolling six-week period until it is clear that normal operations are possible. This will give airlines certainty of network operations and that years of investment in building up their route networks are not under threat because of circumstances beyond their control.
With the UK government (through ACL) becoming the first nation to adopt JNUS principles for the benefit of airlines and their passengers, time will tell whether other airport coordinators in other countries follow suit, following IATA’s guidance.
Featured image: Cerib / stock.adobe.com
