West said the strike is a concern for production and will make it harder to meet production targets for the best-selling 737 MAX jet. This is the first strike at Boeing since 2008. RELATED | 'No end in sight': Striking union says 1st round of mediation with Boeing didn't get far The strike adds to other problems for Boeing, which is under scrutiny from U.S. regulators after several safety issues, including a door plug that blew off a jet taking off from Portland in January.