Revenue grew 2.1% to €5.02 billion, of which passenger revenue was €4.42 billion, up 3.4%.
Meanwhile load factor rose 1.5 percentage points to 80.5% and passenger numbers rose 8.5% to 23 million.
Willie Walsh, IAG chief executive, said: “We’re reporting another strong quarter performance… our positive passenger unit revenue trend continued with an increase of 3.5% at constant currency. This trend benefitted partially from the timing of Easter.
"Despite higher market prices, our fuel unit costs have gone up by just 0.6% in euros.
At current fuel prices and exchange rates, IAG still expects its operating profit for 2018 to show an increase year-on-year.
Both passenger unit revenue and non-fuel unit costs are expected to improve at constant currency.
Walsh did not mention the 4.6% stake IAG took in Norwegian Air last month.
