A Spirit Airlines jet takes off above two United Airlines airplanes at Newark Liberty Airport on March 23, 2018 in Newark, New Jersey.LONG BEACH, Calif. — United Airlines CEO Scott Kirby on Thursday predicted Spirit Airlines is going out of business and said the once-profitable discount airline model is dead.Spirit Airlines filed for Chapter 11 bankruptcy protection late last month for the second time in a year, after it failed to make deep enough changes during its first attempt only to be met with weaker ...