Total revenues at Aer Lingus fell by 16% during the first three months of 2009 compared to the same period in 2008.
Aer Lingus shares were down 17% at 57c in Dublin this lunchtime.
In a statement, the airline also announced a re-organisation of its senior management structure in an effort to meet the new challenges of a deteriorating outlook for the industry.
Aer Lingus says the management overhaul has been taken to reflect the different needs of its short haul and long haul operations.
In today's trading statement, Aer Lingus said its passenger numbers in the three months to the end of March fell by 6.5% year on year to 2.09m.
Short haul passengers decreased by 5.7% while it also saw a 12.5% decrease on its long haul routes.
At the same time, the airline's short haul capacity fell by 4.5% and its long haul capacity slumped 19.5%.
Aer Lingus also said that its short haul average fares fell by 1.6% in the first two months of the year, but tumbled by 23.6% in March.
This brought the quarterly figure down 10.8% year on year. However, this decline was partly offset by the strong increase in ancillary revenues per passenger, which rose by 14.5%.
