By Rajesh Kumar Singh and David Shepardson CHICAGO/WASHINGTON (Reuters) -JetBlue Airways Corp is not taking no for an answer in its quest to buy rival Spirit Airlines. On Monday, the New York-based carrier launched a hostile all-cash takeover bid for Spirit Airlines, two weeks after the ultra-low-cost carrier rejected an offer from the larger rival. JetBlue, which in early April offered $33 per share, is locked in a takeover battle for Spirit with Frontier Group Holdings and has argued a deal will help better compete with the “Big Four” U.S. airlines that control nearly 80% of the passenger ma…