Understanding Airport Slot Cancellations in a Global Pandemic – What the Numbers Say

As reports of decreasing flights become more and more familiar, ACL’s Data Analyst, Chris Butler, looks at how cancellation activity can help us understand how allocated slots have declined, as well as what to expect as the summer season progresses.

Following the granting of widespread alleviation from the use-it-or-lose-it rule for Summer 2020 there have been extensive cancellations of airport slots as a result of widespread travel restrictions, meaning that slot volumes have been substantially reduced. Airport Coordination Limited (ACL) has seen weekly slot volumes fall as low as 9% of the volume seen last summer, with weekly allocated seats falling further to less than 4% of last year’s volume in April.

Significant reduction in slot volume was first seen at the end of Winter 2019, where total allocated slots declined by 5.2% from the beginning of March to the end of the winter season, a fall of over 70,000 slots. Slot decline accelerated through March, with weekly volumes falling to just 60% of the volume seen in the previous winter season.

This decline only worsened as the Summer 2020 season began. At the beginning of June, total allocated summer season slots at UK airports were 48% lower than at the same point last year. This represents a sharp decline, with a deficit of over 730,000 slots year on year.

To date, decline in slot volume has substantially affected the early months of the Summer season, as airlines focus on their schedules held at the beginning of the season. By observing the total slot volume at monthly snapshots we can see how slot decline at the beginning of April was focussed on the first month of the season, with decline further into the summer months emerging at subsequent monthly snapshots.

Slots scheduled in June fell by 73% from the beginning of May to the beginning of June (a decline of over 185,000 slots), indicating the rate at which slots are being cancelled. These monthly snapshots show significant slot decline continuing as the season progresses, resulting from airlines cancelling slots on a piecewise basis due to resource restrictions and continued uncertainty regarding the possibility of increased flying.

As of 1 June, using S19 weekly slot volumes as a comparison, substantial decline is seen as far as the end of June (W13), where allocated slots are currently around 30% of the volume seen last year with some airlines yet to cancel slots held in July.

This currently represents a slight increase versus May, where slot volume was around 10% of last year’s volume. Caution should be taken however when looking further into the season (where slot volumes remain as high as 95%) as analysis of cancellation patterns indicates that slot decline is expected to roll into the coming months, as airlines amend their schedules further into the summer.

This chart breaks down the total cancelled slots by the month that those cancellations were made. The data indicates the pattern seen in cancellation activity, suggesting that the remaining summer volume will also reduce as cancellations reach further into the summer months. The scale of this reduction, however, is difficult to predict whilst the ongoing challenges posed by travel restrictions and quarantine periods remain unclear.

Whilst positivity is emerging from airlines regarding the re-introduction of air travel this summer, any uplift in flying will be difficult to forecast due to the rolling nature of cancellation activity. Despite this, ACL’s industry relations and the analysis of our schedule data will allow us to identify the early indications of any increases in flying, which may enable other members of the aviation industry to prepare for the challenges that an uplift in flying will bring.

By Chris Butler- Airport Capacity Analyst

Copyright © ACL Airport Coordination Limited Ltd. All rights reserved.
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