Originally Posted by
Beer Baron
My understanding is that there are certain classes of ticket that allow free changes of flight and others (cheaper ones) that do not. Obviously the airline will not let you change flights for free on the cheaper ticket as then there is no incentive to purchase the higher ticket class.
While there is no cost to the airline on the day to allow you onto the earlier flight, they will damage their ability to charge you (or anyone else) more for a higher ticket class in future. Why would you pay for something if you can get it for free.
Yep. They're called full fare and discounted. Generally any full fare ticket will allow you to change as many times as you like, a discounted ticket will have restrictions and a fee... although there are some types of ticket that are middle of the road that will allow changes within certain parameters - e.g. within 72 hours of departure, etc. or similar (don't quote me but something along those lines).
Generally, the more you pay, the more flexibility but total flexibility comes with paying full fare.