Talks between Ryanair and the pilots’ union Fórsa have been adjourned this evening.
Discussions, which were in their fourth full day, ended without agreement and the parties are expected to resume talks at some stage next week.
Both sides are attempting to resolve differences over base transfers, promotions, annual leave and other issues.
The talks follow a five-week long dispute which has resulted in five days of strike action by around 100 of Ryanair's 350 Irish-based pilots.
Earlier, Bernard Harbour of Fórsa was hopeful of reaching an agreement with Ryanair.
He had said the fact that mediator Kieran Mulvey was continuing with negotiations suggested, he thought, that there was the possibility of reaching agreement today.
Mr Harbour said a "fair bit of business has been done" during the three days of talks that took place earlier this week, and the union was entering today's discussions with a positive view.
However, he said there was still a number of issues to be resolved.
With no agreement reached today, the talks are expected to resume next week.