A pair of federal lawsuits filed in San Francisco and New York accuse Delta Air Lines and United Airlines of misleading passengers by charging premium fees for window seats next to blank walls. A New York law firm brought the cases as proposed class actions on behalf of any passengers who say they wouldn’t have selected or paid more if they had known their seats did not include a window. Both Delta and United declined to comment, citing pending litigation. The lawsuits claim that Alaska Airlines and American Airlines also sell windowless window seats but disclose the information during the selection process.