Airlines across the U.S. are working to dig out from the longest nationwide ground stop in 25 years. More than 2,000 flights were canceled Saturday. The more than four-hour ground stop has stranded passengers and forced professional and college sports teams to scramble to find alternate transportation to games. Trump administration officials say new technology being added to the nation’s air traffic control system overloaded antiquated equipment and caused intermittent communications and radar gaps. A limited number of domestic flights have departed since the stop was lifted but the effects could be felt for days.