Nonunion airport workers at Chicago’s O’Hare International Airport said they would strike on Nov. 29 as part of an effort to win the right to organize and to raise wages to $15 per hour, according to the Service Employees International Union.

The SEIU, which wants to organize more airplane cabin cleaners, airport janitors, baggage handlers and wheelchair attendants who work for vendors to the airlines, said the strike will expand to demonstrations and protests—but no job actions—the same day at 18 other large U.S. airports...