it had nothing to do with night or landing lights, the issue is the plane looks as if it is floating.
It has *everything* to do with fixing the landing lights because, in order to fix them, we had to raise the airport hard surface a little bit, to prevent that problem. Don't you think we should know, having made the scenery AND the fixt, why this problem happens, regardless if you think they might be related or not ?
So, as I've said, you will either have:
1) shadows over the landing lights and the airplane sinking wheels if the hard surface is lower than the terrain mesh
OR
2) no problem with landing lights but the airplane wheels very slightly raised, if the hard surface is higher than the terrain mesh
OR
3) ground textures and airplane shadows flickering with the terrain mesh, if they are exactly the same height
We decided to go for solution 2, that's it. The problem doesn't happen with P3D, because the scenery use a different method for ground textures, not possible in FSX, so there's no ground flickering.