These latest allegations keep the company and union head-to-head
British Airways has been accused of "a cyberspace witch-hunt" after it suspended 15 cabin crew members.
The airline said it had acted over "inappropriate postings" made on the website of union Unite, adding it would not tolerate "intimidation of staff".
But Unite, which is currently balloting 13,000 BA staff on strike action, says the alleged comments were made on Facebook and not on its website.
The union would "vigorously defend" its members, a spokesman added.
Unite said it doubted the suspensions were solely to do with internet posts.
The two parties are locked in what is an increasingly bitter and tense fight for the company's future.
BA wants to make big changes in the terms and conditions of its staff.
The company wants three quarters of its crew to accept pay rises of 2-7% followed by a pay freeze.
It also wants 3,000 staff to switch to part-time working, along with a reduction in onboard crewing levels to 14 from 15 on long-haul flights from London's Heathrow airport.
A 12-day strike that had been planned over Christmas was halted after the High Court said it was illegal following concerns about how the ballot had been organised.
The new strike ballot among cabin crew opened on 25 January and conclude on 22 February, the union recently said it would not strike over the Easter period.