Key TakeawaysSpirit Airlines stock was down about 50% in afternoon trading after a judge blocked a planned merger with JetBlue.The U.S. Department of Justice had sued to block the deal, saying it would stifle competition and hurt consumers.Judge William Young said "cost-conscious" travelers would suffer if the deal went through.Spirit Airlines (SAVE) shares dumped more than 50% on Tuesday after a judge blocked its proposed merger with rival JetBlue (JBLU).JetBlue’s planned $3.8 billion acquisition of discou ...