Flt Planning
Many airlines will have a department called Navigation Services, ATM, performance dept or just plain old Flight planning.
These folks maintain the route databases for the flight planning systems, update all the flight plan routings as per the RAD / 28day Airac cycles, update Jepps, carry out route & airport analyses, maintain runway performance software, issue nav and atm notices, possibly run the company tankering policy and carry out fuel policy analyses and the more experienced ones will be performance engineers with technical writing ability. These guys n gals can save an airline alot of money and are more than just flight dispatchers although many of them may have started their careers as such.
It's one of the most interesting back-office jobs at an airline.
A good book that touches on some of these topics is "Optimising Jet Transport Efficiency" by Carlos Padilla.
D.O.G