More than 33,000 Boeing employees ended their strike a month ago. But planes have only just recently started moving along the assembly lines that were idled by the two-month work stoppage.

Boeing said Tuesday it has restarted production of its bestselling 737 MAX jets, nearly three months after the jet makers' machinists union began a debilitating strike. Some 33,000 machinists returned to work in November after ratifying a new four-year labor deal.

Boeing restarted production of its best-selling 737 MAX jetliner last week, about a month after the end of a seven-week strike by 33,000 factory workers, according to three sources familiar with the matter.