IAG chief executive Willie Walsh told Sky News on Friday (5 June) the policy, which will come into effect on Monday (8 June), had "torpedoed" BA’s chances of resuming flight operations in July.
Walsh’s comments came after BA and IAG declined an invitation to attend an industry roundtable with home secretary Priti Patel and aviation minister Kelly Tolhurst.
"It’s terrible," said Walsh. "I wrote to MPs last night [Thursday] to say this initiative has, in effect, torpedoed our opportunity to get flying in July.
"We think it’s irrational, we think it’s disproportionate, and we are giving consideration to a legal challenge to this legislation."
Walsh said the policy had been pushed through without consultation with the aviation sector, and speculated other carriers may also be considering legal action.
"We’re reviewing that [a legal challenge] with the lawyers later on today," said Walsh. "I suspect that there are other airlines who are doing so.
"It’s important to point out there was no consultation with the industry prior to enacting this legislation. We do believe it’s an irrational piece of legislation."
BA was criticised by MPs in the Commons this week for announcing plans to cut up to 12,000 roles, around a quarter of its workforce, while placing more than 30,000 employees on furlough.
Walsh said BA and IAG was consulting with its unions, and that no decisions on redundancies had yet been made.
However, the airline is facing growing pressure from union leaders – particularly after snubbing Patel and Tolhurst on Thursday.
"British Airways’ workers, passengers and shareholders deserve to know why the airline’s management refused to attend the meeting with ministers," said Unite general secretary Len McCluskey.
"This is a company that claims to be in crisis.
"The government has opened the door and the entire UK aviation industry is meeting – airline carriers and airports – in an effort to find a way through this crisis. It is unbelievable and, frankly irresponsible, that BA would sit this out.
"Thousands of airline and airport jobs across this country are currently hanging by a thread yet BA spurns the opportunity to work with industry and government to pull together at this time of huge upheaval."
However, during a TTG Face To Face interview on Friday (5 June), PC Agency founder Paul Charles, one of the leads behind the sector-wide "quash quarantine" campaign, said BA had been "wise" not to attend the roundtable because they had sensed the government was simply not listening.
"This is a government that shows no understanding of how the travel industry works," said Charles. "There is palpable anger among travel and tourism businesses."
