Ryanair are hoping to prevent further flight cancellations by taking back one week of its pilots' holiday, but they can't guarantee more disruption.
Pilots at London Stansted, Dublin, Frankfurt and Berlin have now been offered an additional 10,000 euros per year, O'Leary told a news conference.
Ryanair's chief executive Michael O'Leary yesterday admitted to a "cock up" over pilot shortages that led him to cancel flights and disrupt the plans of hundreds of thousands of passengers.
The BBC reported that in a letter seen by it, pilot representatives from 30 of the company's 80 or so European bases have turned down the cash bonus offer. Some pilots were said to be hoping for a permanent pay increase, in addition to the bonus. With pilots rejecting the latest offer, there is a risk of more cancellations in the future.
The low-priced carrier said last week it would cancel as many as 50 flights a day until the end of October after misallocating pilot holiday until the end of the year.
He added:"I don't even know how there would be industrial action in Ryanair".
"Since there is no requirement in aviation regulation to provide annual leave per se, it is unclear what is compelling Ryanair to provide any leave to their pilots at this time", the association said.
They urge Ryanair to engage with them in order to agree better working conditions, and say they will only be fulfilling the terms of their contract - and will work no overtime - until improved contract terms are in place. Out of a total of 103,000 Ryanair flights in the next six weeks, only 2100 flights were cancelled.
"We haven't been sent anything yet", O'Leary said when asked about the letter.
The Irish Air Line Pilots' Association said 140 Ryanair pilots left for Norwegian Air in recent months. O'Leary also said he didn't anticipate this crisis would affect the company's previous earnings guidance.
CEO Michael O'Leary says they're entitled to do it as per the pilots' contracts and doesn't believe it will cause problems.
The airline expects to have refunded or processed alternative routes for 95% of affected customers by the end of this week.