The airline said the cancellations were because of a change in the way pilot's annual leave is calculated meant that too many were granted four-week breaks.
DEFIANT Ryanair pilots will take their holidays as they team up against boss Michael O'Leary after he suggested they were lazy.
Stranded holidaymakers say they are having to wait up to nine days to get home and others have been in tears trying to get through to a jammed helpline that can cost £25 or more.
He accused some pilots of being "precious about themselves" and "full of their own self importance".
He added:"I don't even know how there would be industrial action in Ryanair".
'Piloting is very highly skilled, but I challenge any pilot to explain how it is a hard job or how they are overworked, or how anybody who by law can't fly more than 18 hours a week could possibly be suffering from fatigue, ' he said.
Irish law allows Ryanair to avoid recognising trade unions but several sources said that both pilots and cabin crew are forming informal groups to increase their bargaining power, while taking advice from worldwide labour rights groups.
He added: "To our pilots, thank you for those of you who have been coming in on your days off".
He revealed some pilots had been offered €10,000 (£8,700) rises as their wages were "a little on the low side".
Some 315,000 Ryanair customers are expected to be affected by the cancellations over the next six weeks, but the airline's investors have had a pretty smooth ride-the airline's share price rose on Friday, almost back to where it was before the scheduling snafu emerged.
"We make mistakes. This time we made a major boo boo", said Mr O'Leary.
John explained that Ryanair is appealing to young pilots because you can get a lot of hours clocked in the air and then use those hours clocked to get a better job and move on. Ryanair will complete training for a further 120 pilots within two weeks, and will recruit 500 new pilots over the next six months, Mr O'Leary said. We will be reasonable. "We don't need their agreement.it is in their contracts". It's also understood that pilots at some Spanish bases have already begun a work-to-rule pattern.
"I seriously regret these cancellations and upsetting and worrying 80 million of our customers last week".
One pilot told Mail Online: "There are reports of lots of pilots joining BALPA union".
"By the end of this week over 95% of customers will be rebooked or refunded".