Alliance are a serie of different mods. On the Star Wars GC, you can play the civil war Empire vs Rebel era + Black Sun and soon the Republic and CIS.
This is one new feature, a 4th faction. This new side named "Free Side" because it is the join from all Pirate planets. Players will can choice the new side only on the galactic conflict named Birth of the Rebellion.
This is not a stupid faction, how you can see on screenshots it builds units and it can realize attacks around all the galactic map. Have fun.
what kind of aircraft will their be?
The Free Side uses units from all the other sides. They are the neutral/pirate planets. Even they use structures from the Black Sun, Empire or Rebel.
So basically they are a mix?
Yes with a few changes on fleets and ground units.
The point from the 4th faction is see it playing as other IA faction. Free Side IA is not sleeping all time, it attacks other planets, it builds units, shipyards and more.
epic!