JetBlue and Frontier shares rose by about 5% as Spirit Airlines announced a wind-down, ending its 34-year run. The move could give rivals more room to gain market share and reduce the competitive fare wars across the U.S. industry. Spirit had 4,119 domestic flights scheduled between May 1 and May 15, offering 809,638 seats. JetBlue, which had previously outbid Frontier in a $3.8 billion deal, plans to expand at Spirit's largest hub, Fort Lauderdale-Hollywood International Airport in Florida with service to 11 new cities.