Airbus has told workers at its Montreal-area A220 factory that it wants to impose mandatory overtime on weekends to catch up on delayed production of the money-losing jet, three sources familiar with the matter told Reuters.

Members of Airbus's Canadian division are meeting the International Association of Machinists and Aerospace Workers (IAM) union on Wednesday to discuss the plan, said the sources who spoke on condition of anonymity.

Reuters sources say the issues this time concern its 787 widebody planes.

The discussions comes as concerns mount over supply problems at the world's largest planemaker.

Reuters reported last month that Airbus faces a new wave of industrial pressures from parts and labor shortages with several dozen aircraft expected to enter the assembly process with additional delays in the second half.

Industry sources have said the single-aisle A220, which has roughly 110 to 130 seats, is already among the models most heavily affected by production delays. The effect of recent delays on Airbus' overall delivery target of 800 planes this year remains unclear.

Analysts say Airbus sets its delivery targets conservatively but the buffer against any further industrial setbacks appears to be dwindling.

Reuters reported that productivity slipped in March at the Montreal-area Airbus factory, one of two A220 manufacturing sites, as the plant's 1,300 workers engaged in pressure tactics during contract talks. The A220 workers reached a deal in May.

Airbus is trying to grow production of the A220 jets to a combined 14 planes a month in 2026, spread between the factory in Mirabel, Quebec, and a plant in Mobile, Alabama. That would be up from six a month in December 2022, the latest publicized rate.

An Airbus spokesperson declined comment on production planning and internal matters, but reiterated that jet deliveries will be backloaded towards the second-half of the year and the operational environment remains complex.

Christian Bertrand, president of the Machinists' union local that represents the A220 workers, said "before imposing overtime, there are mechanisms to respect within the collective agreement."

Unions have recently capitalized on tight labor markets to press for more flexible working conditions. Unionized workers at Airbus's U.S. rival Boeing (BA.N), opens new tab, for one, want to end mandatory weekend overtime during their current contract talks with the planemaker.