Alaska Air (NYSE:ALK) has agreed to pay $2.6B for Virgin America (NASDAQ:VA), beating rival JetBlue's (NASDAQ:JBLU) bid (and leapfrogging the carrier) to become the fifth-largest U.S. airline by traffic. Alaska's offer of $ 57 per share in cash represents a premium of about 47% to Virgin's Friday's close, and will allow it to heavily expand its presence on the U.S. West Coast. Virgin America is 54% owned by Richard Branson's Virgin Group and New York-based Cyrus Capital Partners.