Pilots have rejected proposals to forgo their annual leave
Ryanair has announced plans to recruit 125 new pilots within 'the next week or two'.
The announcement comes just hours after a letter was sent to the company by a group of its existing pilots, rejecting an offer of a tax-free €12,000 bonus in exchange for working overtime.
Workers have also discussed industrial action which is feared could worsen the current situation.
It is reported the draft letter, signed by Ryanair pilots, has warned they will 'work to rule'.
The pilots also say the details around the €12,000 offer are too vague, particularly with regards to the number of days off pilots who accept the bonus would have to give up in order to qualify for it.
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.
The airline has come under increasing pressure over the past week after it revealed that an issue with staff leave meant thousands of flights would have to be cancelled.
Chief executive Michael O'Leary announced the recruitment drive at Ryanair's AGM meeting in Dublin.
It has previously dismissed reports that the loss of 140 of its pilots to a Norwegian rival this year has planned a role in the cancellations.
The airline reportedly offered pilots the €12,000 bonus in exchange for agreeing to work extra days, in order to avoid having to cancel even more flights.
The bonus was apparently contingent on pilots having logged at least 800 flight hours over the course of the previous year.
Ryanair is cancelling 103,000 flights over the next six weeks, with affected customers being e-mailed with offers of alternative flights or full refunds.
It says it has taken on extra customer service staff to speed up the backlog of flight change requests and refunds.
Ryanair expects to have processed over 300,000 alternative routings or refunds for customers - over 95% of affected customers - by the end of this week.
Ryanair’s Kenny Jacobs said: "We apologise sincerely to each and every one of the 315,000 customers whose original flights were cancelled over a six week period in September and October, while we work to resolve this short term rostering failure.
"We have taken on extra customer service teams to speed up the rate at which we accommodate and action alternative flight requests or refund applications.
"We expect to have the vast majority of these completed by the end of this week.
"The vast majority of these requests are being dealt with online, but as our call centres and chat lines are extremely busy, we ask affected customers to bear with us as we do everything we can to respond to their requests and try to resolve any problems we have created for them, for which we again sincerely apologise."
Additional reporting: IRN