Passengers are facing a third day of disruption at Heathrow as British Airways cancelled short-haul flights after a global computer crash that unions blame on the outsourcing of IT services to India.
The embattled airline said it was cancelling 13 short-haul flights from Heathrow Airport, Europe's busiest, but was aiming to operate a full long-haul schedule from the hub and was operating a full service from Gatwick Airport.
Thousands of passengers were left stranded over a busy holiday weekend in Britain after BA scrapped hundreds of flights worldwide. Experts warned the knock-on effects could continue for several days.
The airline urged passengers to check their flight status online before travelling to the airport in a bid to avoid scenes seen over the weekend when people camped out at Heathrow.
The GMB trade union said the disruption "could have all been avoided" if BA had not cut hundreds of IT jobs in Britain and transferred the work to India.
But the airline denied the claim and said it was making "good progress" on restoring normal service.
"As our IT systems move closer to full operational capacity, we will again run a full schedule at Gatwick on Monday and intend to operate a full long-haul schedule and a high proportion of our short-haul programme at Heathrow," a spokeswoman said.
"We apologise again to customers for the frustration and inconvenience they are experiencing and thank them for their continued patience," she said.
- 'Power supply issues' -
Some British media suggested Monday that BA could be hit with a bill for compensation costs of more than £100 million (115 million euros, $128 million).
The airline has blamed the computer crash on a "power supply issue" but has not offered further details.
BA cancelled all its flights out of Heathrow and Gatwick on Saturday after the IT failure, which shut down all of the carrier's check-in and operational systems and affected call centres and its website.
Passengers were asked to contact BA to locate their luggage, after many were forced to leave Heathrow without claiming their bags in chaotic scenes that saw queues snaking out of the airports.
The glitch did not appear to be a cyber attack.
Britain is still recovering from a ransomware attack that crippled crucial infrastructure earlier this month, including shutting down access to patient records at the state-run National Health Service.
BA's outage came on a busy weekend in Britain, where Monday is a public holiday and many schoolchildren are beginning a week's holiday.
The carrier said it was "extremely sorry" for causing inconvenience over the holiday period.
British Airways has suffered other IT glitches recently, leading to severe delays for passengers in July and September last year.
IAG, the parent group of British Airways and Spanish carrier Iberia, earlier this month reported a 74-percent slump in first-quarter net profit to 27 million euros ($30 million), due in large part to a weak pound.