 The AP is reporting that as a result, Delta shares tumbled by 6% in midday trading on Thursday, and the shares of other carriers were dragged down as well. JetBlue, American, United, and Southwest fell between 3% to 6%. But don't feel too bad for the Atlanta-based airline. Delta said it earned $1.31 billion from April through June. Now that is down from $1.83 billion a year earlier.