I noticed that most of the documentation and tutorials are on finding the path on the ground, but what about if you have a flying objects and can fly around or even over the obstacles? What would the best approach to this problem be using A*?
This is something usually named 3D pathfinding. It is not supported by the A* pathfinding project since it uses a lot of memory and is really slow.
If you have a static world, you can do something with point graphs, manually placing nodes at relevant positions.