Machinists (IAM) members at three Lockheed Martin locations are on strike after voting overwhelmingly to reject a company contract offer that reduced health care benefits and dropped defined-benefit pensions for newly hired workers. Some 3,700 members are on strike in Fort Worth, Texas, Edwards Air Force Base in California and Naval Air Station Patuxent River in Maryland.

“This is ground zero in the health care and pension fight,” said IAM Southern Territory General Vice President Bob Martinez. “This is a nationwide fight to take good health care and pension benefits from working families, and our members…are determined to prevail.”

The IAM has filed several charges with the National Labor Relations Board against the company, including charges of direct dealing, bargaining in bad faith and unlawful spying and surveillance.

The Machinists at the Fort Worth facility build F-16 and F-35 fighter jets. Those at the Edwards and Patuxent River bases perform flight tests.

Find more about the issue here.