Look at it another way: I am flying from city A to city B. There is a direct flight from A to B, another flight that goes from A to C to B and another route which is from A to D to E to B. The way it is often priced, the direct flight from A to B is most expensive, and the flights that connect are cheaper, (probably because they take longer.) If priced by distance, then the flight from A to C to B might cost A to C plus C to B, and be 2 or 3 times more than A to B. And A to D to E to B would be too expensive to list.