British Airways is entering a third day of chaos after its computer systems brought flights to a halt over the bank holiday weekend - and its chief executive has said he won't resign over the fiasco.
Many flights have resumed, however, short-haul routes from Heathrow airport are still affected. The airline is warning customers to check before they travel and that there may be "congestion" when they arrive and further delays on long-haul flights.
"We operated a full schedule at Gatwick on Sunday. At Heathrow, we operated virtually all our scheduled long-haul flights, though the knock-on effects of Saturday's disruption resulted in a reduced short-haul programme," the airline said in an update on Monday morning.
Passengers scheduled to travel on flights on Monday have been told they can get a refund for their ticket, even if is scheduled to run, as have those expecting to get short-haul flights on Tuesday.
British Airways, owned by International Airlines Group (IAG), faces a potential multi-million pound bill for the delayed passengers and cancelled holidays.
Three days of chaos caused by an IT glitch at Delta airlines last year was expected to cost the US carrier $150m in lost revenue.
And BA has been criticised by GMB Union for outsourcing IT to India last year. "This could have all been avoided," said GMB national officer for aviation Mick Rix.
"BA in 2016 made hundreds of dedicated and loyal IT staff redundant and outsourced the work to India. BA have made substantial profits in for a number of years, and many viewed the company's actions as just plain greedy".
However, BA's chief executive and chairman Alex Cruz told Sky News it was not down to outsourcing. He also confirmed that 75,000 passengers have been affected speaking in his first media appearance since the incident began.
And the BBC reports Cruz has said he will not resign after the chaos. He has been boss of the British carrier for just over a year after leading fellow IAG airline and Spain's second largest carrier Vueling.
Meanwhile, he turned to YouTube to assure customers directly, saying the company was "doing our very best".