Originally Posted by
nerd
Good question.
Since the seat can be re-sold at the then-prevailing rate for that flight's inventory, what if there's not a loss in revenue, but an increase, if the seat gets sold at a higher price?
Why do assume it will be resold at a higher fare? If the airline expected to be able to sell it at a higher fare then they wouldn't have sold it to you at a lower fare. If the airline is good at YM then it will almost always cost the airline revenue.
I would agree that the fee is arbitrary, sometimes the hit is less then $100 and sometimes more, but it absolutely costs the airline revenue. Furthermore, if there was no change fee then people would game the system and tie up far more inventory.