I travel a lot and use flight search engines quite a bit. CheapOair.com has been my only bad experience so far, and I would strongly discourage anybody from using them. I booked a ticket with them, got an email with confirmation number, reference number and itinerary. Hours later, get a new email telling me that due to a technical error the price at which I booked the ticket could no longer be guarantied ... I call customer service, and the same flight I got a confirmation number for was not even available...other flights were and at higher prices... Forget them! read full review »