Ryanair scrapped 82 flights on Sunday, the start of a six-week program of cancellations it's making as it seeks to reduce a backlog of crew vacation required by Irish regulators before the end of the year.

"We have messed up in the planning of pilot holidays and we're working hard to fix that," Kenny Jacobs, Ryanair's chief marketing officer, said in a statement Saturday.

Ryanair will offer refunds or alternative flights to affected customers. Credit:Bloomberg

In the statement, the Dublin-based carrier said it expected to cancel 40 to 50 flights daily, "with a slightly higher number this weekend."

Ryanair will offer refunds or alternative flights to affected customers over the period, it said in a statement on Friday, adding that the cancellations, which amount to about 2 percent of its network, won't have an impact on earnings in September and October.Between 308,000 and 385,000 passengers could be impacted over the period, according to data compiled by Bloomberg based on the airline's passenger statistics.