The Boeing Company, whose order books are bulging with demand for its planes, was hit by its second major strike in three years early Saturday, when the union that represents 27,000 machinists in Washington State, Oregon and Kansas walked off the job.

The union, the International Association of Machinists and Aerospace Workers, said its members struck Boeing at 3:01 a.m. Eastern Daylight Time after last-minute talks, held in Florida, failed to bring an agreement. No new talks were scheduled.

A Boeing spokesman, Tim Healy, said Sunday that there had been no developments in the negotiations over the weekend. Boeing does not plan to build airplanes while the strike is under way, Mr. Healy said, although it will deliver finished planes that have been certified by the Federal Aviation Administration and will provide service to planes already in service.

However, its plants will remain open and employees who are not members of the machinists union are expected to come to work. Boeing’s contracts with its other unions bar them from conducting sympathy strikes, the company said on its Web site.