Fresh strike action by French air traffic control staff will force airlines to ground hundreds of aircraft across Europe this week.
The walkout will run from Wednesday evening into Friday morning (March 21-23) affecting a number of UK carriers and plunging flight schedules into disarray.
Both easyJet and Ryanair have already been forced to make cancellations, and are warning passengers to check before they travel with more expected - potentially at short notice.
Ryanair said: “We regret to advise customers that due to an air traffic control strike in France, we have been forced to cancel some flights. Unfortunately, further flight delays and cancellations are likely.”
British Airways said: “We are expecting further periods of industrial action... on the evening of March 21 and all day on March 22.
“We are sorry that your flight could face disruption, which is beyond our control, and we recognise that you may not wish to travel as a result.”
easyJet said: “We have been advised of a national strike in France starting on the evening of March 21.
"Like all airlines, our flights to and from French airports, as well as those flying in French airspace, could be affected.
"We expect there will be delays and cancellations due to the industrial action.”
Passengers travelling with easyJet will be able to transfer flights free of change or receive a refund, with hotel accommodation and meals provided where required.
Jet2.com added it was aware of the strike and apologised for any inconvenience.
All passengers are advised to check the status of their flights before travelling and any guidance from their airline.