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's defence operations faced disruptions on Monday as thousands of union workers went on strike, halting assembly lines for fighter jets and missile systems. The strike began after members of the International Association of Machinists and Aerospace Workers (IAM) District 837 overwhelmingly rejected Boeing's latest contract offer.

About 3,200 union members at Boeing facilities in Missouri and Illinois went on strike at midnight on Monday after rejecting an offer from the company, the union said.