Think about it differently and throw out the textbook. Because fares are in part determined by the input costs that airlines incur in the production process. Hence my fare for flying is payment for my share of the service the airline is providing. If the airline does not use fuel costs as one ioda of a factor in determining their fares, then fine, I will defer....but that is not the case. If a plane was flying at full capacity with everyone on board weighing 100 lbs side by side a plane flying full capacity with everyone on board weighing 300 lbs would the costs of the flights be the same, all else being equal? No. Therefore, if an airline uses fuel costs as a variable in their price determinate, then it can be said that my fare is payment for (in part) the share of the fuel costs that my weight incurs. In this sense, I, at say 100 lbs, am paying a higher pewrcentage of the fuel costs then someone weighing 300lbs. Is that not price discrimination?
I understand the textbook definition of price discriminations in varying degrees.
