BA chief executive Alex Cruz told a parliamentary select committee the airline was running at 25-30 per cent of its normal flight schedule, prompting it to cut thousands of jobs because "fewer flights means fewer people required to actually service them".

"This is the worst crisis that British Airways has gone through in its 100 years of history," he said on Wednesday. "We're still fighting for our own survival.

"We are taking every measure possible to make sure we can actually make it through this winter. We do not see a short-term coming back of our passengers. All the feedback we get ... is still pointing at a slow recovery process."

Britain's leading airline has been heavily criticised by politicians and unions for laying off 13,000 staff and renegotiating the contracts of many of its remaining employees.

It says it has no choice because it is burning through STG20 million ($A35 million) a day and straining the finances of parent company IAG, which is in the process of raising 2.74 billion euros ($A4.4 billion) from shareholders.

Cruz has cut his own pay by about a third.

UK-based airlines have benefited from government employment retention schemes and loans but have not had the kind of industry-specific support deployed in France and Germany to bail out Air France-KLM and Lufthansa.

Cruz said a return to flying had been hampered by the weekly changes to quarantine rules and the lack of a testing system at airports.

Australian Associated Press