score:3
tl;dr: do not, ever, try to find logic in airline pricing. There is, but it's beyond human understanding.
The airline tries to maximize its profits and once it decides to fly a plane from point A to point B its costs are pretty close to being fixed regardless of how many seats it can fill. So, it'll try to fill it to the brim while asking the most money it can. Obviously cheaper tickets are easier to sell but more expensive tickets bring more profits. So it has very sophisticated systems making a prediction on how much demand will there be for a given route at a given point of time and it will compare to the supply on said route and set price accordingly. This is so badly not based on distance that you can fly from city A to city C with a transfer in City B cheaper than flying from city A to city B -- (ab)using this is called hidden city ticketing.