Boeing is resuming production of its bestselling plane, the 737 Max, for the first time since 33,000 workers began a seven-week strike that ended in early November.

The company said Tuesday that plane-building resumed at its plant in Renton, Washington, after going through a process of training workers and identifying and fixing potential problems.

Boeing shares rose 4.5%, their best single-day percentage gain in nearly four months.

Production and deliveries of Max jets and another airline plane, the 787 Dreamliner, have been stopped several times in recent years to fix manufacturing flaws.

“Our team has worked methodically to restart factory operations in the Pacific Northwest. We have now resumed 737 production in our Renton factory, with our Everett (Washington) programs on plan to follow in the days ahead," the company said in a statement.

Boeing builds its 777 and 767 jets in Everett, north of Seattle.

Separately, the company said it took orders for 49 planes in November but lost an order by U.K. carrier TUI for 14 Max jets. It delivered 13 planes, down from 56 a year earlier.

Ever since a panel called a door plug blew off a Max operated by Alaska Airlines in January, the Federal Aviation Administration has capped Boeing’s production of Max jets to 38 per month. Boeing hopes to convince regulators that it has corrected quality and safety issues and can raise that number to 56 planes per month.

Boeing has been losing money since 2019, after two Max jets crashed, killing 346 people. It needs the cash it earns from delivering new planes to begin digging out of a deep financial hole.

New CEO Kelly Ortberg has announced plans to lay off about 17,000 workers and sell new stock to raise cash and prevent the company’s credit rating from sliding into junk status.