IAG has reported a second-quarter operating profit of €805 million, up from €555 million a year ago.
Operating profit before exceptional items in the six months to June 30 was up 37%, to €975 million.
Chief executive Willie Walsh said the result was a ‘very strong performance’.
IAG said the IT failure, which left thousands of customers disrupted and unable to check in their baggage over the second May bank holiday, cost it €65 million (£58 million).
Passenger unit revenue rose 1.5%, or 4% at constant currency.
Walsh said: "The underlying trend in unit revenue improved, benefitting partially from Easter and a weak base last year.
"Non-fuel unit costs before exceptional items are up, at constant currency.
"These costs include the financial impact of the power failure which affected British Airways’ customers."
He added sales for the group’s long-haul flights from Barcelona for low-cost carrier LEVEL, launched in June, continue to be ‘well ahead of our expectations’.
"We’ve ordered three additional aircraft and are considering other European bases for the operation," added Walsh.
