The Italian antitrust authority on Wednesday opened a probe into Ryanair for alleged improper commercial practices over the Irish low-priced airline's mass cancellation of flights, including over 700 in Italy.
Ryanair is facing an estimated bill of £17 million in compensation payouts to customers as a result of mass cancellations over the next six weeks.
A significant number of Ryanair pilots have rejected a request to work additional days to alleviate a pilot shortage that has caused the cancellation of over 2,000 flights in the coming weeks, a source close to the pilots said on Wednesday.
It says all 315,000 customers received emails on Monday advising them of flight changes and offering alternative flights, refunds and EU261 notices.
In a press conference, Ryanair CEO Michael O'Leary apologises to customers affected by the flight cancellations and acknowledges that the airline "messed up".
Jacobs added:"We apologise sincerely to each and every one of the 315,000 customers whose original flights were cancelled over a six-week period in September and October, while we work to resolve this short-term rostering failure".
James Daley, director at Fairer Finance, another consumer group, said: "Ryanair has made this mistake and it needs to be gong out of its way to help customers claim what they are rightfully owed".
The airline said it was cancelling flights at airports where it ran the busiest schedules so it would be easier to place passengers on alternative flights.
O'Leary revealed that about 400,000 booked flights will be canceled.
More than 120 pilots at the budget airline attended meetings in Dublin this week where a ballot for industrial action was discussed, and colleagues are set to meet across Europe today and tomorrow to consider collective action.
Ryanair says the disruption is because of difficulties it is having managing a transition of its leave year from an April to March model, to the calendar year of January to December, as required by European regulations.