(Reuters) - Boeing is expected to make an improved wage offer on Thursday to the union representing over 33,000 of the planemaker's striking U.S. West Coast factory workers, three sources familiar with the matter told Reuters.

The workers, who produce Boeing's strongest-selling 737 MAX commercial jet and other planes, have been on strike since Sept. 13 and have rejected two earlier offers from Boeing.

(Reporting by Allison Lampert, David Shepardson and Joe Brock; Editing by Chris Reese)