Navigation Fee's

[azflyer]

What are they, and what causes them to flucuate???

[NorgeFly]

Air traffic control mainly I think, but also when you acquire slots for new routes the one off slot charge is billed as a navigation fee too.

[Aahz the Pervect]

What are they, and what causes them to flucuate???

I believe the fluctuation is due to the rise and fall of supply.

[Powi]

When openting / editing a route, you are (usually) paying for airport slots. Those payments are listed under navigation fees.