Boeing has delivered layoff notices to more than 400 members of its professional aerospace labor union, part of thousands of cuts planned as the company struggles to recover from financial and regulatory trouble as well as an eight-week strike by its machinists' union.

Boeing will lay off more than 2,500 workers in the U.S. states of Washington, Oregon, South Carolina and Missouri, according to federally required filings posted on Monday and a union official, as part of the debt-heavy U.