Four Canadians aboard Ontario-based air ambulance missing off U.S. coast

An extensive marine search is ongoing in the waters off Nantucket for a missing air ambulance that was carrying six people, four of whom are Canadian employees of a private Ontario-based medical flight company.The U.S. Coast Guard said in a statement that “search crews located a debris field that has been confirmed to be associated with the missing aircraft,” a Gulfstream G100 on its way from L.F. Wade International Airport in Bermuda to Boston Logan International Airport before los