France’s aviation authority the DGAC has warned of “severe” disruption, calling on airlines to halve their schedules ahead of the walkout.
More than 1,000 flights have been cancelled as a French air traffic control strike upends hundreds of thousands of travellers' plans.
The industrial action - which started at 6am Friday 16 September and will run to 6am on Saturday 17 September - has forced airlines to radically slash their schedules, as other planes reroute around French airspace.
France’s aviation authority the DGAC has warned of “severe” disruption, previously asking airlines to ground half their flights ahead of the walkout and urging passengers to delay trips.
“Flight cancellations and significant delays are to be expected,” the DGAC said in a statement.
“Passengers who can are invited to postpone their trips.”
In more bad news for passengers, the French air traffic control union has added three extra strike days.
Workers will walk off the job on Wednesday 28 September, Thursday 29 September, and Friday 30 September.
Which airlines have cancelled flights because of the French strike?
Air France has cancelled 55 per cent of its short and medium-haul flights and 10 per cent of its long-haul flights on Friday 16 September.
Ryanair has cancelled 420 flights, affecting 80,000 passengers.
In a statement, the airline hit out at the 'unjustified' strike.
"It is inexcusable that passengers who are not even flying to or from France are disrupted," said Neal McMahon, Ryanair operations director.
McMahon called on the EU to introduce legislation to protect overflights - flights that travel through a country's airspace - from short notice cancellation.
easyJet has reportedly cancelled 'hundreds' of flights, according to French news organisation The Local.
“Like all airlines operating to/from French airports easyJet expects some disruptions to its flying program and has been requested by the French CAA to proceed to cancellations," an Easyjet statement reads.
Together with Volotea, these five airlines operate around 64 per cent of all flights scheduled to depart in France on Friday.
Other carriers have also cut their schedules. Brussels Airlines have cancelled two flights on Thursday evening and 10 flights on Friday.
Why are French air traffic controllers striking?
The French Syndicat National des Contrôleurs du Trafic Aérien (SNCTA) union - the country’s main union for traffic controllers - called the strike over pay and working conditions.
In a statement, the union said inflation was eroding worker pay, calling for wage increases and more recruitment.
“Between 2029 and 2035, one third of the [air traffic control] workforce is retiring. It is imperative that we anticipate and plan recruitment,” the statement says.
“If not, the consequences will be inevitable in terms of the public service, working conditions and flexibility.”
Will my flight be cancelled?
Air France and easyJet have said they will contact every passenger individually.
“The company regrets this action, which will have significant consequences for customers,” an Air France spokesperson said.
The DGAC has advised passengers on other airlines to reach out to their carrier for more information.
If your flight is cancelled, you are likely entitled to a full refund or a seat on another flight.
If you are flying over France, your flight may not be impacted - the DGAC is collaborating with Eurocontrol to help airlines avoid French airspace.
The Union plans a second strike for 28-30 September, but this may be called off if the air traffic controllers reach an agreement.