Aer Lingus has warned that its controversial 97 million euro cost-cutting plan may not be enough to secure the future of the airline.
Fuel costs, the economy, a three-week cabin crew strike and late Easter break all contributed to an operating loss of almost 56 million euro in the first three months of the year.
Christoph Mueller, Aer Lingus's chief executive, admitted the airline had a challenging start to 2011.
"Our performance was affected by the Impact cabin crew disruption in January and February, as well as difficult demand conditions, particularly on leisure routes from Ireland," he said.
"While we still expect that Aer Lingus will be profitable in 2011, we expect that the level of profitability will be much lower than in 2010.
"In light of the continued weakness of the Irish economy and pressures on non-controllable costs, we are assessing whether the Greenfield cost reduction programme is sufficient to protect profitability for the future or whether further measures are required."
The Greenfield programme planned more than 650 voluntary redundancies, pay cuts and a pay freeze.