Does enhanced orbital units mean spaceships ?

I think what Aleran said sounds closest (as well as straight up awesome) to what PA will have. Here is hoping we have exchanges of fire between land and orbit (like the missiles to asteroid in the original concept video).

In saying all this I am interested to see what fighting over Gas giants will be like.

It could be pretty cool to have a couple of capital ships fighting in orbit and slagging from orbit - they could take time to 'warp' between different planets and just fight in an orbital layer - like others in this thread said, battles would most likely take place in important places and it would help with the issue of making a totally new UI for 3d movement space combat. In addition if it were only a few large expensive units rather than swarms of fighters/bombers it would avoid being a 90% copy of the air layer.

I also agree with that. Its probably simpliest aproach.
What could be the option for countering asteroid bases? Sending orbital units? Missile pod with big rocket and warhead instead of commander? Missile barage! Its just the same with setting up bases on another planets. If enemy has base there he could block the way?
This all new and I cant imagine how it will play. But Im guessing with spaceships or without them its going to be lot of fun.