It will take three to six months for Ryanair to get through the backlog of refunds of cancelled flights.
The airline says the large waiting list is due to a limited number of people being available to work in its offices to process claims.
A survey released earlier this week by Which, shows 5% of Ryanair passengers in the UK had got a refund within the time limit set by the EU.
Ryanair CEO Michael O'Leary believes it will take some time for all the money to be given back.
"At the moment, we have 35 million refunds to process," said Mr O'Leary.
"That is just the cancellations from the three months of April, May and June.
"We are already a third of the way through that we have refunded about €400m of about €1.2bn.
"We are doing that with limited staffing because of the social distancing restrictions on people coming to the office.
"It will take us anything between another three to six months to eliminate all of that backlog."
