United Airlines Says It Will Honor Mistake Fares United Airlines says it will honor the tickets it accidentally gave away for free. The decision is good news for people who snapped up the tickets on Thursday after United accidentally listed airfares at $0. Many customers got their tickets for $5 or $10, paying only the cost of the Sept. 11 security fee. Airlines have posted so-called "mistake fares" before. Airlines generally decide on a case-by-case basis whether they'll honor the ticket. United isn't saying how many tickets it accidentally gave away, or how much the mistake cost. The wrong fares were available on its website for a few hours on Thursday. It eventually shut down bookings on its website until it could fix the problem.