Baggage handlers at Gatwick are threatening to strike, accusing bosses of bully-boy management.
Unless ground-handling firm Aviance agrees to negotiate its recent plans for downsizing, GMB members say they are ready to take industrial action.
A meeting of more than 250 union members voted unanimously to resist the new management techniques being brought in.
Union chiefs have accused Aviance of using "macho-management" and bully-boy tactics.
One cost-cutting scheme which has angered staff is having canteen passes revoked.
Local GMB organiser Gary Smith said: "Our members are very determined to fight this issue and unless we hear from Aviance by Thursday that it is prepared to discuss these plans, we will ballot the members for strike action."
If there is no response from Aviance, the 700 GMB members will cast their votes in a secret ballot.
Last week the firm revealed jobs would be lost, voluntary redundancies would be put in place and there would be restructuring as the company launched its recovery plan.
The GMB is not impressed and Mr Smith said: "The company says it has financial problems at Gatwick. We have asked for transparency and openness about the scale of the problem. There is a feeling that the company is not being straight."
He also said Aviance was railroading workers into accepting new working practices.
"Employees are being subjected to the worst kind of macho management. The GMB will not be bullied, whatever the threat. This is not an industry in terminal decline and there will always be a need to put bags, fuel and passengers on aircraft."
Just a few weeks ago the GMB secured a 4.2 per cent pay rise from management with no strings attached.
Mr Smith said: "Now they have hit us with this. It just doesn't add up."
Madeleine Richards, regional organiser for the T&G union at Gatwick, said: "The company has made downsizing proposals which we are scrutinising.
We are concerned particularly with redundancy proposals and proposals to outsource work."
Aviance is one of four ground handlers at Gatwick, including Servis-Air, Groundstar and BA's own baggage operation.
The company blamed recent contract losses on its decision to put a recovery plan into operation.
A BAA spokesman confirmed that if the Aviance's GMB members did strike it would be a localised dispute and would only affect Aviance's contract airlines.
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