Ryanair has been forced to cancel up to 250 flights as an air traffic control strike in France brought chaos to European skies.
Departures from Stansted, Luton and East Midlands airports were all badly hit, with flights to France no longer operating. The airline advised customers to either rebook their flights or seek a refund.
Flybe also cancelled some flights to France on a day when industrial action was expected to impact as many as half of all flights into and out of Paris Orly airport and a third of flights to and from Charles de Gaulle airport.
Eurostar services were unaffected although travellers were warned that both the Paris Metro and overland French rail services could be affected.
The strikes are part of an ongoing dispute between the French government and public sector unions angry at proposals to increase the official retirement age to 62.