It is quite possible that booking a fight online at some websites could land you in trouble which could make you run around trying to solve the problem. Some of the online websites have very poor customer service and they are very inefficient in dealing with flight tickets problems. Those websites usually exist as a price comparison website but they don't actually issue you the tickets. They help you compare prices from different websites and then when you click on them, it takes you to those websites prices shown. Other websites which does issue tickets though, can still give you problems because they serve as any other travel agents. They are depended on the flight airlines booking system and at times the amount of people calling them or booking at the same time, can cause the online travel agent to make costly mistakes. The same goes for the retail travel agents as they could make mistakes too, but at least you can always go back to their physical stores if they are not answering your calls. At worst case scenario, you can get the police involved if you believe that the travel agency is cheating you. If you booked online websites and thing doesn't work out for you, it would be kinda tough to involve the police and sort out your problems.