British Airways (BA) was operating most of its flights from London’s two largest airports on Monday after a computer system failure stranded thousands of passengers over a holiday weekend and turned into a public relations disaster.

The airline planned to run more than 95% of flights from London Heathrow and Gatwick on Monday, Chief Executive Alex Cruz told Sky News.

BA had been forced to cancel all its flights from Heathrow, Europe’s busiest airport, and Gatwick on Saturday after a power supply problem disrupted its operations worldwide and also hit its call centres and website. The disruption continued on Sunday. Some stranded passengers curled up under blankets on the floor or slumped on luggage trolleys, images that played prominently in the media at the start of a week when schools were on holiday.

Mr. Cruz said the origins of the problem, which also hit passengers trying to fly into Britain, had been a power surge on Saturday morning, which affected messaging across BA’s systems. He denied a union claim that the outsourcing of IT work to India had played a part in the failure.