Staffing Problems Force Flight Cancellations: Northwest Airlines canceled at least 500 flights this month because it did not have enough pilots. The Air Line Pilots Assn. estimates that the number could be double that once the final tally is in. The St. Paul, Minn.-based airline is scheduled to meet with union leaders to discuss staffing. Pilots want the airline to increase hiring, but Northwest is expected to favor work-rule changes to allow the airline’s 5,000 pilots to fly more. The canceled flights accounted for 1% of Northwest’s January total. Northwest is hiring pilots at the rate of 42 per month, but the union says that is barely enough to cover retirements.