"We remain available for talks with Unite at any time without preconditions."
Marc Meryon, industrial relations partner at the law firm Bircham Dyson Bell, said BA's case rested on whether Unite took enough care in ruling ex-employees out of the ballot.
"The outcome of the case will depend on how many people they have balloted who have left, and how long ago they left," he said.
"If the union has been balloting people who left the company six or nine months ago then the company will be saying that it was reasonable to expect the union to have got it right and excluded them [from the ballot].
"But if they are complaining about people who left within the last month or two then it's much more difficult to show that the union was at fault."
Virgin Atlantic said passengers were already rebooking their flights - and that they were providing bigger planes where possible in order to accommodate more passengers.
Flights to New York (Newark), Boston, Washington and Delhi will now be operated by the larger Airbus A340-600, which has 68 more seats than the A340-300 normally used.
"We've sold 3000 seats in the past 12 hours: people are already switching," said spokesman Paul Charles.
Airline analyst Andrew Fitchie of Collins Stewart estimated that Easyjet could be in line for extra revenues of £40m to £60m as a result of the dispute.
Ryanair, Flybe, Lufthansa and Air France will also benefit he said.
Unite announced the result of its ballot on Monday, saying that cabin crew had voted nine to one in favour of strike action, with an 80% turnout.
Cabin crew are unhappy with staff reductions and changes to their working conditions.
BA has conceded that the number of ex-employees included in the ballot is likely to have been small, and so would not materially alter outcome of the vote.
Immediately following the ballot, Unite assistant general secretary Len McCluskey welcomed the result as a demonstration of the strength of feeling surrounding the issue.
"We have taken this decision to disrupt passengers with a heavy heart and we are hoping that the company can still avoid it happening," he said, announcing the ballot result.
If the strike is allowed to go ahead, it is expected to affect up to a million BA passengers travelling over the Christmas period.
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.