The Federal Aviation Administration, worried about the possible effect of labor unrest on air safety, has stepped up its surveillance of airlines with labor-management disputes, the agency's chief said. FAA Administrator T. Allan McArtor singled out Eastern Airlines and said he was disturbed by conflicting reports from pilots at the airline, with some complaining that they have been forced by management to fly aircraft that are not airworthy. The agency has assigned "significantly more surveillance people" to Eastern, he said. McArtor said he has not been able to determine if the allegations are true. He said the FAA also was paying increased attention to other airlines, including Northwest and United, where there have been labor disputes.