Budget airline calls on European Commission to take action, claiming it is the 53rd French ATC strike in seven years.
Airline says it has been forced to cancel 166 flights to, from and over France as French air traffic controllers go on strike again.
Dispute could wipe out second quarter profits but some say that failure of striking pilots to win clear victory is good news for airline's future.
Ryanair has said 26 flights to and from France will be cancelled while easyJet say a quarter of their flights could be scrapped at start of dispute.
Judges rule that airline had illegally given French-based staff Irish contracts in order to save money on payroll and other taxes.
Airline accused of infringing law in contracts with 127 staff at Marseille airport as ruse to avoid paying its fair share of social security and tax.
Investigation starts after professional surfer Toby Donachie, 19, who was supposed to be flying to the south of France, ended up in Sweden.