Several thousand workers at three Midwest manufacturing plants where Boeing develops military aircraft and weapons went on strike early Monday, potentially complicating the aerospace company's progress in regaining its financial footing.

About 3,200 workers who build F-15 fighter jets and other military aircraft voted to reject the firm's latest contract deal.

Despite what appears to be an imminent strike vote by 3,200 machinists at its St. Louis defense plants, Boeing’s leadership is expressing confidence that major programs, such as the F-47 fighter, will not be significantly affected.