Eurocontrol director general Raul Medina said summer 2023 would prove a particular challenge owing to the effects of war in Ukraine on available airspace, and the potential for further industrial action – such as that ongoing in France for much of the year – to impact European ATC capacity.

According to Eurocontrol, there will be around 33,000 daily flights traversing the continent over the next two months – an increase of around 8% year-on-year.

The Times reports Eurocontrol has issued warnings specific to several potential pinch points, including "high overloads" of traffic overflying Reims in northern France and Marseille in the south, as well as for Athens and Budapest, which could result in airlines being forced to take longer routes.

Warnings have also been issued for Barcelona, Brussels, London, Nicosia, Warsaw and Zagreb for peak days, particularly Fridays and summer weekends. UK holidaymakers are forecast to make more than 25 million overseas trips alone in the period to September, predominantly by air.

While predicted volumes fall short of summer 2019 levels, when daily flights exceeded 37,000, airspace demands are greater owing to several factors including the war in Ukraine, which Medina said had reduced available airspace by 20%; a fall in ATC staff owing to the pandemic; and an increase in industrial action.

Medina said it was imperative that all stakeholders – particularly airports and ATC operators – are sufficiently staffed, and that airlines stick to their schedule.

In late May, Ryanair chief Michael O’Leary called for overflights to be protected during periods of ATC strike action, with the state whose ATC staff are striking bearing the brunt of any flight cancellations; for there to be at least 21 days’ notice of any action; and for there to be binding arbitration before any action takes place.

On the threat of summer strike action, Medina – who according to The Times was addressing a meeting of Airports Council International – added: "Recent industrial action caused many delays across the network. We can manage situations like that in quieter periods, but if it happens in the middle of summer, it will be much more challenging. We need to be prepared."