The potential bankruptcy of a rival lifted shares on the prospects of less competition.Shares of JetBlue (JBLU 8.54%) rallied on Wednesday, up 12.4% as of 2 p.m. ET.The airline appears to be benefiting from news that a big rival, which JetBlue actually tried to acquire last year, may go bankrupt. A bankruptcy of a key competitor has the potential to benefit other airlines, especially smaller ones like JetBlue.Spirit preparing to file for bankruptcyToday, The Wall Street Journal reported that rival low-cost ...