On Tuesday morning, JetBlue Airways (JBLU -10.76%) announced that its CEO is stepping down at a critical moment in the airline's history. The market hates surprises, and shares of JetBlue were trading down by more than 10% as of 12:25 p.m. ET following the announcement.A new leader at a challenging timeJetBlue has a lot going on right now. It's currently in court fighting an attempt by antitrust regulators to block its proposed acquisition of Spirit Airlines (SAVE -4.99%). It has also had to deal with opera ...