The news came ahead of Ryanair's meeting later in the day with Impact, the union representing Irish pilots.
However, arriving earlier for the meeting with the pilots' union IMPACT, Chief Operations Officer Peter Bellew said that expected a total increase of €100 million across pilots and cabin crew, and that there would be no change to the airline's guidance for profitability.
Having called off proposed strike action for Wednesday, 20 December, IMPACT reiterated its position that its mandate for strike action can be implemented in the absence of an agreement to proposals put by IMPACT/IALPA to Ryanair at Tuesday's meeting.
"We think this is disappointing given all that's been said in the media over the last five days by the company".
Ryanair has said it will recognise cabin crew unions and hold meetings in the new year, as it prepared to start its first ever talks with pilots' unions in Dublin on Tuesday.
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The unions said they gave Ryanair a series of proposals to consider and requested a response by midday (1200 GMT) on Thursday, a schedule which the no-frills airline has not yet committed to. It is the first time in the Irish low-priced airline's 35-year existence that it has agreed to entertain independent unions.
Mr O'Leary said the move was "putting the needs of our customers first, and avoiding disruption to their Christmas flights".
The decision marks a historic turning point for Ryanair, given that O'Leary - in charge since 1994 - had vehemently opposed any union representation for staff.
In engaging with the unions, Ryanair is breaking a 25-year-old policy of pilots dealing directly with Ryanair, although Ryanair was insistent that a Committees of Ryanair pilots should be established to deal with Ryanair issues, as Ryanair will not engage with pilots who fly for competitor airlines in Ireland or elsewhere.