This mod allows you to drive on Dillingham airfield.
This mod adds a collision surface to the far north-west airport of Ohau as well as sharper cleaner Hmap textures. The runway also has some markers for 1/4 mile and 1/2 drag racing. The airfield is enterable using the slip road already present in the original game, the barrier has been removed.
Extract the Rar into your tdu directory.
I may make more changes to this when I get a chance, nothing is truly final.