Hi Amorski,
It all depends on how you use your fleet, and the market you use it in.
You mention airline, and business jets- sounds contradictionary. How large is the operation going to be? Where are you going to be in 5 years' time?
Some of the systems I described will accommodate a regular airline only, as on-the-fly changes to routes, airports, etc. simply take too long to set up. Other systems have a built-in flexibility to easily accommodate operations to and from lake beds, off-airways, remote strips, etc.
If you're keen on squeezing every drop out of your operation and know your cost indices, then I would suggest a cost-index optimzed system- make sure that the projected gains in cost optimization are more than what these systems will cost you.
If your crews are going to slap on tons of additional fuel because they're not familiar with the airports they're flying into (typical ad-hoc operation) then don't bother too much with an accurate system, anything will do then.
A new FPS must suit your intended operation, and can be used as a tool to lift your operation to a higher level, provided that the inputs are correct and are monitored.
Hope this helps a bit.
Max
