Sixteen more Ryanair flights are at risk of being cancelled on Tuesday as strike disruptions escalate without any resolution between the Forsa union and the airline in sight.
Ryanair pilots will strike today, affecting 4,000 customers flying between Ireland and the UK, with the airline labelling the action "unnecessary".
Last night, it emerged 16 more flights were set to be cancelled by the airline on Tuesday after strike notification from the Forsa union representing Irish pilots.
Ryanair last night tweeted a letter it sent to Forsa, urging it to call off its third 24-hour stoppage scheduled for Tuesday.
The letter said Ryanair "calls on Forsa to call off July 24 strike by less than 25pc of our Irish pilots".
The letter, sent by Ryanair's chief people officer Eddie Wilson to Forsa national secretary Angela Kirk, who has been negotiating on behalf of the Irish-based pilots, referred to Wednesday's meeting with Forsa.
"While this meeting was primarily to update the new members of your team, nothing has progressed since we have got no engagement or response from the pilots' committee on Ryanair's proposals," it read.
The airline stated that unless it heard back from the union "we will issue cancellations to passengers on 16 (of over 290) flights to/from Ireland on Tuesday".
The company said it could "readily reaccommodate this small number of customers on other flights", and added: "Forsa's lack of urgency is unacceptable when your committee are unable to engage or negotiate."
But Niall Shanahan, spokesman for Forsa, said: "Ryanair management made no reference to the strike action during our meeting with them yesterday."
Pilots are taking part in a 24-hour stoppage today and are planning another for Tuesday.
Pilots are seeking a master seniority list to give those with the longest tenure the first option on promotions, holidays and base transfers.
Regarding today's action, the airline said 90pc of the 4,000 customers affected had been reaccommodated.
Customer service teams were assisting passengers with refunds, free transfers and alternative flights.
Ryanair will also be affected by strikes from cabin crew in Belgium, Portugal and Spain next Wednesday and Thursday (July 25 and 26). The Herald asked if any of the 300 cancelled flights each day would affect Irish passengers but did not receive any information.
The cabin crew strike has forced Ryanair to cancel 600 flights - 12pc of its daily scheduled traffic - over the two days.
The airline said it had been contacting passengers to make alternative arrangements and has pledged to make additional customer service staff available.