Update - 5.44pm: Ryanair boss Michael O'Leary's claim that short-haul pilots do not suffer fatigue from flying should be investigated over safety concerns, according to a trade union.
Speaking to reporters on the day of the airline's AGM in Dublin, Mr O'Leary dismissed reports that its flight crews were unhappy with their working conditions.
He said: "I would challenge any pilot to explain how this is either a difficult job, or how it is they are overworked or how anybody who by law cannot fly more than 18 hours a week could possibly be suffering from fatigue.
"If there are fatigue issues among pilots ... in short-haul flying it's never as a result of flying."
Brian Strutton, general secretary of UK pilots' union Balpa, said the comments were "wrong" and would lead to safety fears.
He said: "The 18-hour figure that Mr O'Leary has come up with does not seem to have any basis in reality.
"Pilots' flying and duty hours are rightly regulated in order to avoid fatigue. Current EU-level regulations limit pilots' duty hours to 60 per week, and flying hours to 100 in 28 days.
"If Ryanair cared to share their pilots' rosters with us we'd be happy to analyse them for fatigue.
"It is the responsibility of the Irish Aviation Authority to regulate Ryanair.
"I think they should look carefully at these comments by Mr O'Leary and decide whether they could give rise to concerns about the safety culture in that airline."
Mr Strutton described fatigue as "endemic in all kinds of commercial flying".
He said: "To suggest that pilot fatigue in short-haul operations can only occur because of the pilot's activities outside of work is, in our view, wrong.
"Balpa is worried about what message this is giving to pilots and what effect this management attitude has on safety culture.
"Pilots are legally bound to report their fatigue as it can have dangerous effects on pilot performance.
"Ryanair appears to be telling its pilots that if they report, their attitude will be that it's the pilot's own fault.
"This is not a good way to engender an open reporting culture."
Update 2.24pm: Ryanair boss Michael O'Leary has said that some pilots are to be offered a €10,000 annual pay rise on top of a €12,000 bonus payment in a bid to plug staff shortages that have led to weeks of flight disruptions.
Ryanair holds its AGM amid flight cancellation chaos pic.twitter.com/mSlzOqkM1Q— RTÉ Business (@RTEbusiness) September 21, 2017
Michael O'Leary said pilots due to take a four-week block of holidays in the next two months will be told to reduce that to three weeks.
Mr O'Leary said pilots' pay at some of its largest bases "may be a bit on the low side".
He added that pay rises will be offered in areas where there are recruitment problems such as London Stansted, Dublin, Frankfurt and Berlin.
Mr O'Leary was being grilled by shareholders at Ryanair's AGM in Dublin today about the shelving dozens of flights every day over the next six weeks.
Shareholders also heard that 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 this was part of normal recruitment and not linked to the current controversy.
Update 12.03pam: Ryanair chief executive Michael O'Leary has today insisted that there is no problem between the airline and its pilots.
He said however that if pilots "misbehave", "there will be no goodies".
Mr O'Leary was speaking following a meeting with shareholders at the airline's AGM in Dublin on Thursday amid the flight cancellation controversy.
During the meeting he said Ryanair is planning to take back one week of their pilots' holidays to prevent any further flight cancellations.
Mr O'Leary said pilots due to take a four-week block of holidays in the next few months because a change in annual leave rotas will be told to reduce that to three weeks.
He said they will get that week back in January.
When asked about reports that pilots are threatening industrial action Mr O'Leary responded: "If you want and need to ask your staff to give up holidays, no work-to-rule can alter that."
He added: "I don't even know how there would be industrial action in Ryanair. There isn't a union."
He also said there have been no demands for new contracts.
Mr O'Leary continued that the airline has "some goodies" to discuss with pilots but warned: "If pilots misbehave that will be the end of the goodies."
He denied that was a threat to pilots against taking industrial action, saying: "I don't think that can be misconstrued as a threat."
Mr O'Leary accused some pilots of being "precious about themselves" and "full of their own self-importance".
"(Piloting a commercial plane) is very highly skilled but I challenge any pilot to explain how it is a difficult job or how they are overworked," he added.
Mr O'Leary insisted that Ryanair's pilots work under "good terms and conditions".
"There isn't a bad relationship between Ryanair and our pilots.
"We asked on Monday for volunteers to work days off ... we have had huge co-operation and support from pilots," he added.
Referring to pilots' pay he said "maybe we have got it a bit on the low side" and said it would be looked at.
Earlier Mr O'Leary was grilled by shareholders about the shelving of up to 50 flights every day over the next six weeks.
"We make mistakes. This time we made a major boo-boo," said Mr O'Leary.
"A very big block of annual leave (for pilots) was over-allocated for September, October and November," he added
Mr O'Leary said that to help ensure no further cancellations after the six-week period, 500 pilots with a four-week block of leave booked for October and 500 in November will have to work one week of that leave.
"We will tell them, 'we will make it up to you'. We will be reasonable.
"We don't need their agreement.
"(Pilots) are not going to participate in work to rule. They want to succeed," he added.
He apologised to the 350,000 people affected by the cancellations.
"I seriously regret these cancellations and upsetting and worrying 80 million of our customers last week.
"We are working hard and long hours to address the passengers disrupted last weekend.
"By the end of this week over 95% of customers will be rebooked or refunded," said Mr O'Leary.
He also told shareholders the six weeks of cancellations has cost the airline around €25m.
Ryanair is planning to take back one week of its pilots' holidays to prevent any further flight cancellations, the airline's chief executive has said.
Michael O'Leary said pilots due to take a four-week block of holidays in the next few months because a change in annual leave rotas will be told to reduce that to three weeks.
He said they will get the other week back in January.
He refused to discuss media reports that many pilots had turned down offers of a €12,000 bonus and instead demanding improved contracts, warning they will “work to rule”.
At a meeting with shareholders at the airline's AGM in Dublin, Mr O'Leary said the airline does not need the agreement of pilots to take back a week of their leave.
He told shareholders six weeks of cancellations, which he previously admitted was a 'mess', has cost the airline about €25m.
Mr O'Leary again apologised for the disruption, which he said was down to mismanagement of the pilots' rostering system.