Ryanair is faces a compensation bill of more than £17 million for the flight cancellations 'mess' which has left many passengers stranded.
Dozens of flights have been grounded at Stansted airport in Essex and a few a Luton airport in Bedfordshire.
The Dublin-based carrier is shelving up to 50 flights daily over the next six weeks due to mix-up over annual leave for its 4,200 pilots.
Ryanair passengers whose flights have been cancelled may be entitled to compensation.
- What rules apply?
EU law protects passengers whose flights are delayed or cancelled under the Denied Boarding Regulation.
This applies to flights either departing from an EU airport or those that are both arriving at an EU airport and operated by an EU airline, such as Ryanair.
- Are passengers entitled to a refund?
Yes, passengers can claim a refund from the airline.
If they have booked a return flight and the outbound leg is cancelled, they can also claim the full cost of the return ticket.
- What if a passenger still wants to travel?
Ryanair must offer an alternative flight as soon as possible after the cancelled flight.
This will be "at worse" on the following day, Ryanair said.
- Do they get any assistance while they wait?
Delayed passengers are entitled to claim reasonable expenditure for food, soft drinks, phone calls and accommodation.
- What about compensation?
If less than 14 days notice is given for a cancellation, airline travellers can claim up to 250 euros (£221) under EU regulation 261, depending on the timing of the alternative flight.
Customers given more warning are not entitled to a payout.
- Is compensation automatic?
No, disrupted passengers must write a letter of complaint to the airline.
They should keep as much evidence as they can, such as boarding cards and receipts to claim expenses.
A template letter can be found on the website of consumer watchdog Which?
The Managing Director of Home Products and Services at consumer group Which? Alex Neill said:
“It’s vital that passengers who have suffered the nightmare of Ryanair’s cancelled flights are now given clear information about what they are entitled to."