Speaking this evening, Bernard Harbour said: "While Ryanair management said they recognised Impact and IALPA (the pilots union) for collective bargaining, they said they were unable to give the union a piece of paper to confirm this recognition".
Impact, the Irish pilot's trade union, wrote on Sunday that they had "suspended a planned one-day strike of Ryanair pilots next Wednesday after company management agreed to recognise the union as the representative of Irish-based pilots".
"We think this is disappointing given all that's been said in the media over the last five days by the company".
"The union reiterated its position that its mandate for strike action can be implemented, after the required notice is given, in the absence of a timely agreement".
It forced the budget airline to recognise a pilots' union and brought about talks with IMPACT union scheduled for later today.
Ryanair said earlier that recognising the unions of pilots and cabin crew will cost them €100m a year.More news: Pentagon Admits to Funding Alien Research Program
"He has said in the past that hell would freeze over before he would recognise unions".
Chief executive Michael O'Leary said last Friday: "Christmas flights are very important to our customers and we wish to remove any worry or concern that they may be disrupted by pilot industrial action next week".
The move marked a dramatic shift after decades of refusing to negotiate with unions and came after groups of pilots around Europe called strikes.
Market analysts anticipate this could increase Ryanair's cost base by up to €150m a year - and even more, if thousands of cabin crew and other support staff also seek union representation.
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.