I'd also encourage you to check out
Starshatter. It's demo is of an older version, but the gameplay is mostly the same in the new version so it isn't that different to the full game. It's a great space sim.
The physics are near-realistic, you can fly anything from fighters to cruisers to carriers, you can fly atmospheric missions and you can command other ships if you reach sufficient rank. If you make admiral and decide to take control of the carrier, it pretty much turns to a strategy game.
It also has dynamic campaigns. Meaning, the missions are somewhat random. You might get a mission to destroy an enemy frigate, for instance. If you fail and have to retreat, you won't get "mission failed". This means you can do multiple hit-and-run attacks to get rid of bigger enemy ships.
If a ship is lost, it's lost forever. It won't come back for another mission. This means that if i decide to take control of a fancy cruiser and lose it because of my incompetence, the fleet has one less cruiser. You fail a mission, you face the consequences, instead of getting "mission failed". You don't have to reload the game after a failed mission. The game continues, but of course your fleet will probably be weakened, if you lost something valuable.
I bought the full game a while ago. It was definitely worth it.
