Three Boeing defense plants face a strike as 3,200 machinists walked off their jobs. Members of the International Association of Machinists voted to strike.

The IAM union represents about 600,000 members across aerospace, defence, airlines, rail, healthcare, and more in the U.S. and Canada, making it one of North Americas largest industrial trade unions.

Boeing machinists went on strike Monday morning, after the union rejected the company's contract offer for the second time in two weeks.