Spirit Airlines lowered its revenue estimate, citing a decline in non-ticket revenue. That refers to things like bag fees and picking your own seat, which can cost hundreds of dollars. In June, United's CEO criticized the ultra-low-cost carrier business model, saying customers "hate it." Insider Today NSIDER TODA Sign up to get the inside scoop on today's biggest stories in markets, tech, and business — delivered daily. Read preview Bull Thanks for signing up! Access your favorite topics in a personalized f ...