Ryanair CEO Michael O'Leary has complained that those strikes disrupt the ability of airlines to cross through French airspace, where overflights represent about 15% of European traffic, according to Eurocontrol.

Source: https://www.ibtimes.co.uk/analysis-easter-travel-warnings-pile-pressure-european-airlines-1714928

Still, the possibility of overflights resuming would have a major impact on carriers.

Source: https://newsinfo.inquirer.net/1817907/who-wants-to-fly-over-taliban-held-afghanistan-new-faa-rules-allow-it-but-planes-largely-avoid-it

“That number could be growing,” he said, but low visibility during overflights made damage assessment nearly impossible.

Source: https://www.nytimes.com/2023/05/06/world/canada/wildfire-western-canada-evacuation.html