Passengers booked on flights which are delayed or cancelled may be entitled to compensation.
Here are some of the key questions around the claims process:
EU law protects passengers whose flights are delayed or cancelled under Regulation 261.
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.
Compensation is payable when an airline is deemed to be at fault, such as the crew being late, cancellation due to underbooking or an aircraft component failure.
If a carrier can prove disruption was caused by 2extraordinary circumstances" - typically severe weather, air traffic control strikes or a security risk - then it is not liable.
Compensation ranges from €300 for short-haul flights, such as Edinburgh to Dublin, which are delayed by more than three hours, to €600 for long-haul trips, such as London to New York, which are delayed by more than four hours.
Compensation may be payable if a flight is cancelled within two weeks of departure.
Payouts vary between €125 and €600, depending on how much notice is given, the distance travelled and the timing of the alternative flight taken.
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.
Template letters can be found online.