I am building a Dieselpunk-ish science fantasy setting and for aesthetic reasons, I decided to make the aether a real phenomena in the setting. Later I realized that aether could be a tool to justify space combat as commonly portrayed in space opera, that is taking place at relatively slow speed and close range with big slow ships and small fast ones.
I established the properties of the aether in order to create the conditions for space opera style space combat.
The Aether is an omnipresent field of exotic-particles giving space a faint silvery hue. Aether particles flow from the aethereal plane into the material plane and back in an unending cycle.
Aether particles disrupt radar and radio/microwave communication, they also diffuse coherent beams making lasers and charged particle beam weapons useless.
Aether particles can also be used for levitation, through aethereal buoyancy, as well as propulsion. Aethereal propulsion differs slightly from levitation, the act of pushing against the aether generates potentially destructive feedback that must be compensated for; because it could potentially tear a ship apart. An idea I had was that the aethereal feedback compensators scale up poorly leading to a prevalence of small nimble craft.
The Aether field behaves like a fluid (which is air technically) so aether-engine craft maneuver as though they were in atmosphere, and must deal with shifts, currents, up- and down-drafts.
All of the above works, at the very least it doesn't give me any more conceptual headaches; I am however always open to ideas.
However I ran into a problem, if there were other forms of propulsion available no one would use aether-engines, they have far too many complications. The solution that I devised was that people had no choice but to use aether-engines.
The aether-field clings to matter, unless you're using an aether-engine trying to move through it; it is like driving through quick sand, the more you fight the tighter it clings to you. While this works out just fine for slowing down it causes all manner of cosmological problems. So the solution to that was to have the gravity of high mass objects, planetoid-mass and up cause the aether-field to diffuse enough for stellar bodies to move at least somewhat normally.
Before I have to cut the aether from my setting, I ask how to resolve the issues with the aether and it's effect on objects. The solution that I have only opens up more questions. That is that gravity displaces aether for planetoid mass objects and greater. However if that is true then shouldn't a star's mass displace most of the aether in a solar system?
I find my self asking similar question of any sci-fi setting where planetary gravity wells inhibit FTL travel but the Sun's doesn't?