By Dan Catchpole (Reuters) -Striking workers at Boeing Defense in the St. Louis area rejected the company's latest contract proposal on Sunday, sending a strike that has already delayed delivery of fighter jets and other programs into its 13th week.

Roughly 3,200 striking St. Louis-area Boeing workers will stay on the picket line after members rejected a modified contract proposal for a fourth time.

“Boeing claimed they listened to their employees – the result of today’s vote proves they have not,” Brian Bryant, president of the International Association of Machinists union, said in a statement....