before I start a question, please understand if my English is weird.
Okay, so let's say you have a plane with navMesh baked on it. Is it posible to make another navMesh on an object? I want to make "object A" to move around the plane, and make "object B" to move around on the moving "object A".
I might be wrong (never had to do with NavMesh so far) so go ahead and correct me but I would say: No.
The Manual -> NavMesh states
The process of creating a NavMesh from the level geometry is called NavMesh Baking. The process collects the Render Meshes and Terrains of all Game Objects which are marked as Navigation Static, and then processes them to create a navigation mesh that approximates the walkable surfaces of the level.
A static GameObject, though, as the name suggests is static, meaning among other things: It doesn't move!
So as I understand it and if I'm not totally mislead I would say if your objectA is moving, then it is not applicable for a NavMesh.
