Aer Lingus says it cannot rule out the possibility that some routes may be axed in order to cut costs.
The airline's latest financial results show a loss of €22m in the first six months of this year, largely due to rising fuel costs.
Aer Lingus says it plans to review all of its operations over the next few weeks, particularly its long-haul services, to see where savings can be made
There are fears that any new cost-cutting measures could hit staff, but SIPTU says the airline's workers have already delivered savings of €11m and cannot contribute any more.