<P> For travelers to qualify for a low round - trip airfare, some legacy carriers require them to spend Saturday night at their destination . The rule is based on the airlines' assumption that business travelers are more likely than leisure travelers to spend Saturday night at home . For example, a business traveler may depart on a Sunday or Monday and then return home that Friday or Saturday . </P> <P> Business travelers's demand for travel is less elastic and airlines attempt to increase their profits by price - discriminating business travelers and leisure travelers . Business travels are also more loyal to a particular airline, and therefore are more likely to accept a higher price . </P> <P> In early 2000s, the Saturday - night stay rule vanished due to competition from low - cost carriers, which commonly do not impose the rule and often sell one - way fares only . However, the practice of pricing according to Saturday - night stay reappeared in 2008 . </P>

Round trip airline tickets are usually cheaper if you stay over a saturday night