With their contract expiring at midnight on Thursday, the Machinists union at the aircraft giant Boeing announced a tentative contract agreement September 8. It was a shock to many union members. “Insulting,” “Joke of a contract,” and “Hard no” were some of the more polite reactions registered on X in response to the proposal, which would raise wages 25 percent over the four-year life of the deal, but eliminate an annual bonus of 3 to 6 percent of wages.