After rejecting the company's second proposed contract, union members in the St. Louis area began striking Monday. They said they will not stop until they receive a fair deal.

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.

Boeing (NYSE:BA) is confronting a fresh labor disruption as about 3,200 unionized workers at its defense facilities in the St. Louis region walked off the job after rejecting the company's latest contract offer.