The Canada Industrial Relations Board (CIRB) has ordered the union representing striking workers responsible for refuelling planes at Montreal's two major airports to return to the negotiating table immediately, just hours after the employees of Swissport Canada walked off the job on New Year's Eve.

The 108 workers began their strike at 11 a.m. Tuesday, raising the likelihood of further flight delays this holiday season, one day after a snowstorm forced the cancellation of about 50 flights.

The workers, members of the International Association of Machinists and Aerospace Workers (IAMAW), are responsible for refuelling as many as 500 planes a day at Pierre Elliott Trudeau and Mirabel airports. They also include machinists, dispatchers, maintenance workers and mechanics.

They have been without a contract since last March and voted overwhelmingly last weekend to reject an agreement in principle reached with Swissport Canada last week.

Swissport, the only fuel supplier at the two Montreal airports, filed a complaint with the CIRB, claiming the union did not negotiate in good faith.

The CIRB's vice-chair, Louise Fecteau, agreed in part with Swissport, saying in her decision that the union had not fulfilled its obligation "of making every reasonable effort to conclude a collective agreement."

Swissport welcomed that decision, inviting the union to propose a meeting "as quickly as possible."

"Our proposal included compensation increases for all employees that met the majority of the union's demands," Swissport said earlier Tuesday, before the CIRB decision was released.

"What they offered us brought me back to where I was in 2015," countered a union official, Mario Beauchemin. "But it's 2019. That's still not good enough."

Mario Beauchemin, president of the IAMAW Lodge 2301, said he lost a third of his salary in 2011, when Swissport Canada took over the fuelling contracts for Montreal's two main airports. (Valeria Cori-Manocchio)

Check flight status, ADM advises

In its statement to CBC News, Swissport said it had launched a contingency plan in anticipation of the strike.

"We want to reassure the travelling public and our customers that we have the properly trained resources in place to continue refueling activities," Swissport said. "We are working with airport authorities to minimize any disruptions to travellers."

For its part, the Montreal airport authority said it has ensured Swissport has the necessary resources to keep refuelling planes at Montreal's airports despite the strike.

"[We] would like to reassure passengers that operations are continuing at the airport, but that the dispute could result in delays in flight schedules," said Aeroports de Montréal (ADM) in a statement. "Travellers are advised, as always, to check the status of their flight before coming to the airport."

ADM said it will be monitoring the situation continuously and has taken measures with Montreal police to ensure airports remain safe throughout the strike.

Union blames 'contract flipping'

Montreal's airport refuellers last went on strike in 1986, according to Beauchemin, the president of the union's lodge 2301.

He said in 2001, the union reached a stability agreement with the company that used to have the fuelling contract, Cafas.

"We weren't allowed to go on strike for close to 15 years, and then they flipped the contract to Swissport," he said. Beauchemin said he and other employees then saw their salaries slashed.

"Personally, I lost a third of my salary. Right now, I'm making what I was making in 2011," he said. "I also lost all my vacation when they did the flip. I've been here for 20 years, and right now I've got 2 weeks vacation."

$16 hourly wage

The IAMAW's Quebec co-ordinator, David Chartrand, said conditions have been deteriorating for the refuellers at the Montreal and Mirabel airports ever since Swissport took over the contracts.

He said his members are working under stressful conditions for about $16 per hour.

"Whether it be temperatures of -30 or +30, in a snowstorm or in a thunderstorm, those who refuel the Montreal-Trudeau airplanes have to manipulate heavy equipment by themselves," Chartrand said in an open letter released Tuesday.

He said employees have had to deal with increased demands and a higher risk of accidents.

"We're very underpaid, and they're going to realize that. It's a very important job. We're not putting food on the plane, we're putting fuel," said Dimitri Metrakos, who has worked as a refueller for more than 20 years.

"We all love what we do. It's who we are, it's what we are but we're just not paid what we think we're worth," he said.

For travellers, 'messed up' plans

Abdel Hani Ghend, who was awaiting his flight at Pierre Elliott Trudeau Airport Dec. 31, was complacent about the prospect of more delays. (CBC)

At Trudeau airport, passengers had mixed feelings about the strike.

"I do believe that workers have rights, and as long as they're doing it peacefully I'm supportive of them," said Abdel Hani Ghend, who was waiting for his flight at the airport.

Caroline Christie was hoping to head home to St. John's, N.L., for New Year's Eve, but her flight had already been delayed because of weather conditions Tuesday morning. She feared the strike will further delay her travel plans.

"They want more money, but on the other hand we have to keep the passengers safe during this busy time. They shouldn't have picked New Year's Eve to go on strike because that's going to have a big effect in the airport," said Christie.

"Our plans for New Year's Eve are pretty well messed up right now."