About 260 maintenance workers at Aéroports de Montréal represented by the union of employees of Montreal airports (SEDAM) have voted in favour of strike action to speed up contract talks.
Union officials insist that passenger service at Trudeau airport will not be affected, but the same might not be true for cargo flights at Mirabel.
The workers are responsible for snow removal on runways, plumbing, carpentry, and the other maintenance work.
Salaries, subcontracting, and the length of breaks are key issues in the contract dispute.
The workers have been without a contract for a year.
Tuesday night, union members voted unanimously in favour of actions that include a general strike to put pressure on their employer.
Last year, the union met with ADM, but the two parties failed to agree on several points.
Union representative Denis Vigneault says the ADM of wants to outsource work to private companies that provide the same services as employees, but at a lower cost.
"The strike would cover both airports, but we would still have to provide essential services and ensure the health and safety of the public. At Mirabel, if air traffic is stopped, it does not put anyone in danger. But Dorval [Trudeau airport] flights should continue because we will provide essential services," said Vigneault.
The union and the employer will meet again on December 19, which the union said is the deadline for ADM to avoid the strike.
The ADM said it will respond publicly today.