British Airways-owner IAG reported a quarterly profit, swinging into the black from a seasonal loss for the first time, helped by lower fuel costs and an improvement in performance across its three airlines.

The airline group, which is in the process of trying to acquire Aer Lingus to expand its stable of carriers, on Thursday reported an underlying operating profit of €25 million ($28 million) for the three months ended March 31.

That compared to the loss of €150 million ($165.4 million) it made last year and an analyst consensus forecast for a loss of €3 million ($3.3 million).

European airlines tend to run at a loss in the winter first quarter of the year when fewer customers fly, and earlier on Thursday IAG's rival Air France-KLM reported an operating loss of €417 million ($459.8 million).

IAG maintained a forecast for operating profit of €2.2 billion ($2.42 billion) in 2015, which it upgraded in February on the back of Iberia's return to growth and cost control across the company.

The airline said that the rate of profit improvement would slow in the second quarter due to the timing of Easter and an adverse fuel price comparison with the same period last year.

In the first three months of the year, fuel costs were down 11 per cent on a constant currency basis, IAG said, helped by more efficient aircraft.

IAG did not provide an update on its plan to acquire Irish airline Aer Lingus, a process which is currently stalled pending a decision by the Irish state on whether to sell its 25 per cent stake in Aer Lingus, a condition of the deal. - Reuters