SEATTLE, Wash. (Metro) -- Senator Maria Cantwell is wondering where the next generation of Boeing workers will come from. Channel Four says she commented during a tour of Machinists, Incorporated, a Seattle Boeing supplier. She says she plans to hold a Senate Aviation Subcommittee hearing on the question this week. Cantwell says a lot of Boeing people are about to retire and retraining unemployed people for aerospace would help. Copyright © 2012 Metro Networks Inc.