Pricing for an individual seat is not cost plus, it can't be.
Yup. Never has been. Never will be.
Gibon2 needs to go away, do a great deal of bed time reading and then come back with a more realistic viewpoint on how airlines work !
A trip to the local library to peruse a few issues of
Journal of Revenue and Pricing Management might be a start if you want a cutting-edge view on the matter, otherwise a few theoretical books on the subject of Revenue/Pricing/Yield management.
As ExXB says Gibon2, the airline business is cut-throat and highly-competitive and a vast number of business inputs are fed into the magic black box that spits out the prices. The basics such as cost of fuel, staff, lease on the aircraft is only really the start of a very long list indeed.......