American could not get us to our destination without a two day delay. Our original flight that caused the rescheduling was delayed, they said, because of weather. The weather was perfect at both ends of the route and other carriers on this route were not having weather delays. So we picked an alternate route, and for the last leg we had to rent vans to drive ourselves to our final destination. American would NOT pay for the rental vans nor refund our tickets.
Like all greedy businesses that abuse the public, the simple truth is that the airlines require supervision.
It should be passenger plus luggage weight if it is just the physics driving the pricing. So fat people with little or no luggage should pay the same as small people with lots of luggage if the total weight of service is the same.