Boeing Co. said it has resumed production across its range of aircraft programs at factories in the Pacific Northwest after they were shut down for weeks because of a lengthy workers strike.

Boeing said aircraft deliveries in November were at the lowest in four years, with all of the planes that were handed over built prior to the strike and delivered out of inventory.

Since the end of a strike in November, Boeing has struggled to restart production of its 737 Max jet, in part due to supply chain issues.

Boeing aims this month to fully resume final assembly of commercial aircraft in the Pacific Northwest, having so far held off from rebooting the lines after machinists ended a 53-day-strike in early November.

Boeing has resumed production of its 737, 767, and 777 aircraft models after a seven-week strike involving over 30,000 workers.