Ryanair boss Michael O'Leary has said it will take up to six months to refund passengers for flights cancelled because of the coronavirus pandemic.
He said the airline was struggling to process a backlog of 25 million refunds with reduced staff, reports the BBC.
However, he pledged: "If you want a cash refund, you will receive a cash refund."
Ryanair is set to cut 3,000 jobs - 15 percent of its workforce - as it restructures to cope with the coronavirus crisis.
It said the 3,000 posts under threat were mainly pilot and cabin crew jobs.
There are likely to be pay cuts of up to 20 percent for remaining staff, the airline added.
O'Leary told the BBC that the planned cuts were "the minimum that we need just to survive the next 12 months".
He said that if a vaccine was not found, "we may have to announce more cuts and deeper cuts in future".
Michael O'Leary, whose pay was cut by 50 percent for April and May, has now agreed to extend it for the remainder of the financial year to March 2021.
Litigation lawyer Jonathan Compton, a partner at law firm DMH Stallard, took issue with the idea that ticket refunds could be delayed.
"Where a flight is cancelled, the legal position is clear, the airline must provide a full refund within seven working days," he said.
"Regulators need to get more active here. The relevant regulator is the Civil Aviation Authority (CAA). The CAA must start instructing airlines to start making refunds, no ifs or buts, and it needs to do this now."