(Reuters) - North American aerospace factory workers seeking to reduce mandatory overtime and lock in four-day work weeks are facing some pushback from planemakers trying to increase production to meet soaring demand for jets.  

Manufacturers have had to make some concessions due to a tight labor market after a wave of COVID-19-induced retirements, but the big planemakers are not receptive to certain demands.

In aviation, improved work-life balance has joined higher pay as key demands from pilots to aircraft mechanics after hybrid work weeks emerged after the pandemic. But big scheduling changes on the factory floor could weigh on manufacturers' efforts to produce more commercial jets.

Workers at Boeing ( BA ) currently in negotiations want to end mandatory weekend overtime, but that has emerged as a sticking point in the talks for nearly 33,000 unionized Boeing ( BA ) factory workers whose membership voted on Wednesday for a strike mandate, according to union officials.

Boeing's ( BA ) largest union has said members are ready to vote on Sept. 12 to strike if needed. A labor disruption would hamper the U.S. planemaker's expected ramp-up of output of its strong-selling 737 MAX jet to around 38 a month by year-end.

"We've made some good improvements in limiting the amount of designated overtime, but it's not good enough," said Jon Holden, president of the Seattle-area local union that represents workers on 737 MAX and other jets. 

Boeing ( BA ) said on average, fewer than 1% of its employees work mandatory weekend overtime. "We know our employees value their time outside of work," it added.

Boeing's ( BA ) jet production has slowed sharply this year following increased scrutiny from regulators, airlines and lawmakers following a January incident when a door plug blew off an Alaska Airlines jetliner while in mid-air.

FAMILY TIME

Scheduling is challenging for aerospace, in part because the sector needs experienced mechanics on all shifts to expand production, but older employees have the seniority to avoid working odd hours. 

European giant Airbus would not agree to four-day weeks for A220 evening-shift workers in their recent contract because the existing schedule is needed to support the jet's ramp-up, said Eric Rancourt, a union official with the International Association of Machinists and Aerospace Workers (IAM) in Quebec.

Industry sources have said the money-losing A220, which seats roughly 110 to 130 people, is already among the models most heavily affected by production delays. The European planemaker recently cut key industrial and financial targets.

Airbus, which wanted to impose overtime in June, has since assigned the extra hours on a voluntary basis, said Christian Bertrand, president of the local union representing Montreal-area A220 workers.

Andy Voelker, a talent specialist at consultancy McKinsey & Company, said younger workers entering the workforce have higher expectations about workplace flexibility. About a third of the U.S. aerospace and defense manufacturing and engineering workforce is aged 55 and above, he said. 

Some mechanics are making gains. Boeing ( BA ) is acquiring Spirit AeroSystems ( SPR ), which agreed in 2023 to make mandatory overtime voluntary on Sundays, and Montreal-area evening-shift workers at business jet maker Bombardier have negotiated a four-day week. Bombardier declined comment.

According to a McKinsey analysis this month, industry demand for talent is higher than the available supply, and this could cost a median-sized aerospace company $300 million to $330 million per year in lost productivity.

The IAM, which also represents the Boeing ( BA ) workers, is pressing for limits on mandatory overtime during the week as well, Seattle union official Holden said.

Unlike office employees who were able to work from home during the pandemic, mechanics often had to take unpaid leave.

"We're never going to be able to work from home, but we do need more time off to be able to spend with our families," he said.