No one would suggest any company selling flights or holidays at a loss BUT many years ago (showing my age folks) a man in Scotland started a business called AA Brothers. They sold booze on the basis that they sold for a small profit but sold shed loads, which they did. Effectively, the company made fortune. If one man can do it then Thomas Cook, Thomson, Jet2 and the others can apply the same formula. Every now and then a cheap flight appears but overall the price of flights ARE expensive.