Crunch talks to prevent industrial action by Aer Lingus pilots are scheduled to reopen.
Management and pilots have accepted an invitation to attend the Labour Relations Commission (LRC), where discussions collapsed in the early hours of Saturday morning.
Tens of thousands of passengers flying from Dublin, Shannon and Cork face travel chaos from Tuesday unless there is a breakthrough between both sides.
Pilots at Belfast and Gatwick have also balloted for industrial action and will serve notice on the company.
Aer Lingus revealed thousands of people due to fly with the airline next week have already changed or cancelled their booking.
"We are still unsure what will happen," said a spokesman. "At this point in time we cannot be certain that we will be able to operate our schedule from next Tuesday. We realise that this is extremely disruptive for our customers and we apologise most sincerely for the major inconvenience this may cause."
Customers can change flights for between Tuesday and Friday free of charge on www.aerlingus.com.
Ialpa, the pilots' branch of Impact trade union, has said the dispute centres on a shortage of pilots in Aer Lingus. It maintained rosters were chaotic last summer, with pilots regularly forced to work six out of seven days throughout the high season.
Senator David Cullinane, Sinn Fein's workers rights spokesperson, said a speedy resolution is necessary to avoid passenger disruption.
He called on the airline management to address the core roster issues which are of such concern to pilots.