Ryanair is facing legal action over its refusal to compensate thousands of customers.
The Civil Aviation Authority has said that customers who had flights cancelled over summer are entitled to compensation under EU law.
Strikes over summer led to many flights to be delayed or cancelled, affecting thousands of UK passengers.
The airline has defended itself and says it does not owe passengers compensation because the strikes were “extraordinary circumstances”.
“Courts in Germany, Spain and Italy have already ruled that strikes are an ‘exceptional circumstance’ and EU261 compensation does not apply. We expect the UK CAA and courts will follow this precedent,” said Ryanair in a statement.
Under EU legislation, passengers can make an EU261 claim when flights are delayed by three hours or more, flights are cancelled or when they are denied boarding.
“As a result of Ryanair’s action, passengers with an existing claim will now have to await the outcome of the Civil Aviation Authority’s enforcement action,” said the CAA.
Rory Boland, the Which? travel editor, said: “Customers would have been outraged that Ryanair attempted to shirk its responsibilities by refusing to pay out compensation for cancelling services during the summer – which left hard-working families stranded with holiday plans stalled.”
“It is right that the CAA is now taking legal action against Ryanair on the basis that such strikes were not ‘extraordinary circumstances’ and should not be exempt, to ensure that the airline must finally do the right thing by its customers and pay the compensation owed.”
Shares in Ryanair (LON: RYA) are trading at 11,44 (0929GMT).