In its first set of half-year accounts since it floated on the stock exchange last year, Aer Lingus has announced pre-tax profits of €11.5m, an €8.3m (42%) fall on the same period last year.
The airline's operating profit was €2.6m. Revenue was up 12.9% to €574m while passenger figures grew by 5.9%.
Recent increases in fuel costs were said to have influenced the airline's margins.
Aer Lingus boss Dermot Mannion said: "(The) operating profit of €2.6m…was achieved in a keenly competitive marketplace where the planned capacity from our competitors in our home bases to Continental routes increased by 45% in the first half of 2007 over the equivalent period last year.
"We operate in a seasonal business, with the majority of our profits earned in the second half of the year. With the substantial increases in fuel prices in 2007, this seasonality influence has had a more pronounced impact on our financial performance in the first six months. Early indications of our performance in the second six months of the year are encouraging."
The airline is maintaining its full-year guidance that trading would be in line with expectations for mid-teen operating profit growth.