In a letter to staff seen by Sky News, the airline warned that it will mean 'moving many more colleagues, from both operational and support function areas onto the government's extended Job Retention Scheme.'
BA, whose owner suffered a £5.1 billion loss in the first nine months of 2020, called it a 'blow to our hopes for the winter season.'
It is the second time the airline has grounded all flights at Gatwick, the previous suspension coming shortly after the first national lockdown in March.
Gatwick airport this time last year, left; and today amid the pandemic, right
'We have made the difficult decision to further reduce our operation for the rest of November.' BA management said in its letter.
'This means far fewer flights than we hoped for in November and means grounding more of our aircraft, including pausing all flights from Gatwick until December.'
Under new restrictions introduced in England on Thursday, overseas travel is permitted only for specific purposes such as work and study for the next four weeks.
Photographs of Gatwick today revealed a desolate terminal under the new lockdown rules.
BA will continue to benefit from Rishi Sunak's furlough scheme after the chancellor today announced a generous new extension to the end of March.
The taxpayer forks out 80 percent of employees wages up to a ceiling of £2,500 under the plan, with employers only saddled with national insurance and pension costs.
In its letter, BA told staff it will focus on 'crucial air links: bringing home the thousands of customers currently abroad, transporting vital goods and ensuring people who are permitted to travel into and out of the UK for work, education and other reasons stipulated by the UK government can continue to do so.'
Last Friday, BA's parent company IAG announced a £5.1 billion loss in the first nine months of this year.
IAG CEO Luis Gallego blamed the pandemic for the reverse in fortune but added it was 'exacerbated' by 'constantly changing' government restrictions.
Instead, he argued countries needed to 'evolve' from quarantines and called for a new pre or post-flight testing system that would release people on arrival.
BA jets grounded due to the coronavirus outbreak parked at Gatwick Airport in Sussex in May during the first lockdown
'We cannot wait until the vaccine to have people flying,' Mr Gallego said. 'We need to evolve from quarantines. They are not the solution.'
Last month, new BA CEO Sean Doyle called on the Government to scrap the self-isolation requirement for international arrivals.
He said the current quarantine system is having a devastating effect on tourism and business travel and called to replace it with a 'test before flying' system.
Speaking at the Airlines 2050 conference on October 19, he said: 'We do not believe quarantine is the solution.
'We believe the best way to reassure people is to introduce a reliable and affordable test before flying.'