Ryanair is cancelling up to 50 fights a day for the next six weeks after the airline made a mistake planning around holidays for its pilots.
The Irish-based budget airline company has already cancelled flights through Wednesday, Sept. 20 as a result of the issue — but more flights will be cut in the next few weeks. Less than 2% of the flights run by the airline will be affected, the company said.
"We apologise to all affected customers for these cancellations," the airline wrote in a statement on Facebook. "We have messed up in the planning of pilot holidays and we're working hard to fix that."
Ryanair is allowing customers with cancelled flights to apply for a full refund or change their flight for free.
The slew of sudden cancellations comes after the company changed the timeframe of its yearly holiday calendar, according to the BBC. The year now runs from January to December instead of April to March, which means the airline company had to grant leave to pilots in September and October, the BBC reported.
The airline has been notifying customers via email or text message about the cancellations, which are expected to impact at least 285,000 travelers, according to BBC.
The next round of cancellations will be announced on Monday, Sept. 18, a representative from Ryanair told Fortune. The representative did not respond to questions about how the company will prevent future incidents like this from occurring.
A number of social media users took issue with the sudden cancellations and called on the airline to release all of the flights slated to be cancelled over the next six weeks. The company has only posted those that have been cancelled through Sept. 20.
Ryanair was still promoting other flight deals and promotions over the weekend despite the announcement of its cancellations.