A resolution has not yet been reached in talks between management and unions representing pilots at Aer Lingus.
Talks are due to continue at the Labour Relations Commission tomorrow.
Both parties are hoping to avert industrial action at the airline which is due to begin next Tuesday.
The dispute centres over a row around rostering.
Aer Lingus is warning that the outlook for the airline's passengers on Tuesday is looking increasingly serious with time to reach a deal running out.
The carrier has said concerned customers can now alter their bookings online for free.