Unite, the union representing the British Airways cabin crew currently on strike, said it plans to issue a new ballot.
The 12-week protective period after the initial ballot, during which striking employees cannot be lawfully dismissed, ends in early June, prompting the union to reballot.
However, Unite cannot ballot on the same issue twice.
Tony Woodley, Unite joint general secretary, told delegates at a policy conference that Willie Walsh, BA's CEO continued "hard-mand stance" would "plunge the airline into a prolonged and totally needless summer of disruption".
Walsh is refusing to back down over the reinstatement of travel perks for BA cabin crew who went on strike.
A deal on cabin crew costs has already been agreed between both parties, with the staff travel issue acting as the final sticking point, according to Unite.
Tony Woodley accused BA of bullying tactics. "There is only one thing to do with bullies - that is stand up to them until they learn some manners," he said.
Woodley said there was "a deal to be done" at BA, that "recognises the real commercial needs and problems of your company" as well as Unite members' "legitimate interests".
The airline is currently in the middle of a second five-day strike period, due to end on Saturday. A third round of strikes is due to start on Saturday.