Low-cost airline easyJet has been criticised for charging passengers a £10 admin fee for a letter to their travel insurers to prove their flight was cancelled.
Stranded customers looking to claim their money back after French air-traffic strikes affected flights earlier in April were asked to provide a letter from the airline confirming the cancellation.
easyJet told passengers they would have to pay £10 for the proof.
According to the Daily Mail, the budget airline defended the charge and said: "The administration charge for the letter is applied because each letter has to be individually researched and created for each passenger."
The Association of European Airlines said it was unaware of other airlines charging for the service.
A spokesman told TravelMole: "We don't do research on all the fees our airlines charge for services but a fee for proof of cancellation is new to us. As far as we know, our member airlines give this service for free."
In a statement, easyJet said: "This is a legitimate cost to help the insurance company process the claim. It will be covered as part of the claim so the customer will be reimbursed."
Thomson Airways warned that the cost of air travel could rise following the court judgement which backed passenger rights over compensation for delays.
Three judges at the Court of Appeal rejected a challenge by Thomson Airways against a county court decision to award James Dawson £1,488.73 for an eight-hour delay he experienced on a flight from Gatwick to the Dominican Republic in 2006 because of crew shortages caused by sickness.
Best flight delay ever? Passengers stranded in Hawaii for three days given £500
What are my rights if my flight is delayed?