I think that there are too many factors to take into account for us to have a real answer to that question. Many are mentioned already like Freight, passenger load, and timing. What about airport fees? JFK would probably be a bit more than Valdosta...

We could figure in the actual cost of the employees on that particular flight based on their individual pay. We could find the actual cost of the fuel that day. It might be easier to figure a fixed overhead cost, but it would vary depending on the type of plane.

We could probably find the actual amount of each ticket on any given flight on any given day with something like Flightaware.com but how accurate is that data?

I wonder how many people actually work in their revenue management department. Maybe the already have this answer and can save us some time.

If we want to speculate, I remember pricing out flights from CVG-DAY. I think it was 63 miles pricing out at 900+ all the time. The big catch is no one actually flew that flight. They would really pay 300+ to go on to somewhere else, so no one was paying that fare.

I always hear how valuable the international routes are, so my guess would be one of those flights.

Interesting question anyway.