I was in a game a few hours ago where my team had already won(basically) so I started messing around with the Z-axis. If you weren't aware, you can set a button to allow z-axis(up and down) movement in the key bindings. I think it might have started out not set to anything, or maybe I set the key it was binded to to something else(I did change a lot of them).

Anyway, from what I could tell it is possible to fly upward/downward vertically and get out of range of turrents. You can use this to get planet bombers away from turrents and bombing a planet without the turrents picking them off. At least thats what it seems like, since the turrents area of fire would be a sphere(they can shoot up), and most people tend to put their turrents farther away fromt he planet rather than closer. So even thought he planet bombers do have a poor range, it is likely that the turrents will be too far away to fire on a ship coming from dirrectly below or dirrectly above a planet. Now alone, this seems alright. Its space! Space is not flat, space has 3 dimensions.

The problem which arrises, is that as far as I can tell you can not build turrents above or below the set level for buildings. This means that even if you know someone is going to try and fly over your planet, you can't build a turrent up there, because there is no way to move buildings along the Z-axis. I tried doing it the same way you move up and down, but the button didn't work. Maybe there is another key binding that can be set in the options, I'll have a look at it latter. The point being made though is that being able to move in the Z-axis can make turrents fairly worthless. They are already easy to fly around, now they can't even protect planets from seige ships very well.

I guess what I'm getting at, is that there should be a way to move buildings along the Z-axis much like there is for moving ships. It just seems reasonable.