EasyJet and Ryanair have been forced to cut about 30% of flights today in the face of a strike by French air traffic controllers.
All airlines serving France or using French airspace face disruption due to the one-day walkout in protest over planned changes to air traffic control practices across Europe.
Flights from the UK to destinations such as Spain, Portugal, Italy, Cyprus, Greece and North Africa face the threat of disruption.
British Airways has cancelled flights from Heathrow to Marseille and Lyon.
The French DGAC civil aviation authority urged airlines to cut services by 10%, particularly on links between France and Spain, Portugal and North Africa.
“EasyJet has been asked by the DGAC to reduce its French flights by 30% and as a result will cancel at least 50 flights to and from Paris Charles de Gaulle, Paris Orly, Basel, Bordeaux, Lyon, Marseilles and Toulouse,” the airline said.
Around 70% of easyJet flights operate through French airspace, meaning there is a risk of delays and late notice cancellations to many other flights, the airline warned.
Ryanair said it would be scrapping 70 flights today while Lufthansa is reducing services to and from the French cities of Lyon and Marseille but that it believed flights to and from Paris Charles de Gaulle airport would not be affected.
While European air traffic controller unions lifted a strike call, two French unions representing about a quarter of all controllers maintained stoppage plans after talks with the civil aviation authority failed.