In a message to the 75,000 people affected by its major IT system failure experienced at the weekend, British Airways chairman and CEO Alex Cruz has apologised for the inconvenience caused and vowed that there would not be a repeat of the incident.
"We are now focusing on making sure that everyone's needs are addressed, we will make an in depth investigation to make sure we get to the bottom to make sure why exactly this happened," he said in a video posted on the airline's Twitter account.
"Absolutely this will not happen again at British Airways."
Cruz said the root of the problem, which also affected passengers trying to fly into Britain, had been a power surge on Saturday morning, local time, which hit the airline's flight, baggage, and communication systems.
The outage also rendered the back-up systems ineffective, he said.
"Once the disruption is over, we will carry out an exhaustive investigation into what caused this incident, and take measures to ensure it never happens again," Cruz said.
The airline chief also reaffirmed that the root cause of the incident was a power supply issue and said there was "no evidence of any cyber attack".
British Airways was forced to cancel all its flights leaving from London airports Heathrow and Gatwick on Saturday as a result of the system failure and Cruz said at the time IT teams were working tirelessly to fix the problems.
Flight compensation website Flightright.com said that with around 800 flights cancelled at Gatwick and Heathrow on both Saturday and Sunday, British Airways was looking at having to pay approximately €61 million in compensation under EU rules. That does not include the cost of reimbursing customers for hotel stays.
Cruz said, however, that the airline would fully honour its compensation obligations.
"If your flight is cancelled, you can rebook for alternative dates any time up until the end of November -- or you can have a full refund," the chief explained.
"All my British Airways colleagues on the ground and in the air are pulling out all the stops to get our operation back to normal as quickly as we possibly can. We are not there yet -- but we are doing our very best to sort things out for you."
As of Monday in the UK, Cruz said the airline was running just over 95 percent of the flights, which was comprised of all of the scheduled long-haul flights at Heathrow and most of the short-haul flights, as well as all flights out of Gatwick.
"We will be making sure that over two-thirds of the 75,000 passengers affected since Saturday -- they will have reached their final destinations at the end of the day today," he said.
By Tuesday, British Airways expects everything will be back to normal.
"Our IT systems are now back up and running and we will be operating a full flight schedule at Heathrow and Gatwick on Tuesday 30 May," the airline's website reads.
British Airways has been cutting costs to respond to competition on short-haul routes from Ryanair and easyJet.
The GMB trade union said the airline's IT systems had shortcomings after it made a number of staff redundant and outsourced its work to India in 2016.
"This could have all been avoided. [British Airways] in 2016 made hundreds of dedicated and loyal IT staff redundant and outsourced the work to India," Mick Rix, GMB National Officer for Aviation, said.
Cruz rejected the union criticism, telling the BBC that the outage was unconnected with the redundancies and the outsourcing of its IT.
"There are no redundancies or outsourcing taking place around this particular hardware live operational systems resilience set of infrastructure in this particular case," he said.
"It's all locally hired, etc, resources that have been attending to the maintenance and the running of this particular infrastructure."
"They've all been local issues around a local data centre, which has been managed and fixed by local resources," Cruz similarly told Sky News.
He also said he doesn't think handing in his resignation in response to the outage would "make much use".