The GMB and Unite unions said a date for a strike ballot would be confirmed in the next few days after hundreds of their members employed by British Airways who work as ground staff and at check-in voted in favour of holding it.
GMB National Officer Nadine Houghton said: “BA forced our members into pay cuts during the pandemic, when they had little workplace power to fight back.
“Now our members are back at work and staff shortages are hammering the company - it is their time to claim back what is theirs.
“These loyal workers have stood by BA through thick and thin, they have kept passengers moving when staff shortages and IT failures nearly brough the operation to a standstill.”
She said staff had “received shocking abuse from passengers”, adding: “If BA wants to avoid industrial action that will trash many people’s summer holidays, they need to do what’s right by check in staff.”
The ballot is not directly for industrial action but to ask members if they would be prepared to take action at a later.
Unite General Secretary Sharon Graham said her members were “left with no choice but to vote for strike action this summer”.
A BA spokesman said: “While this is not a strike ballot, it is a disappointing response from this small group, considering our genuine offer of a 10% reward this year ahead of planned pay talks. Our colleagues are the heart of our business and we are continuing to talk with their union representatives .”
Sharon Graham, Unite general secretary, said: "This is about paying the rate for the job.
"BA has had every opportunity to resolve this dispute through negotiations but it has failed to do so.
"Our members are left with no choice but to vote for strike action this summer.
"Unite will be giving its members its unequivocal support until this dispute is resolved."