Continued staffing shortages in air traffic control facilities are causing delays at airports as the government shutdown nears the one-month mark. Controllers have been working without pay since the shutdown began on Oct. 1, and Transportation Secretary Sean Duffy has been warning that travelers will see more flights delayed or canceled the longer they go without a paycheck. The Federal Aviation Administration reported staffing-related delays on Friday at airports in Boston, Nashville, Houston, Dallas, and Newark, New Jersey. Most controllers are continuing to work mandatory overtime six days a week during the shutdown. Duffy says that leaves little time for a side job to help cover bills, mortgage and other expenses unless controllers call out.