Like in Battlefront there could two flagships (one UNSC, one Covenant). You spawn inside of the ship. Inside the hangar there are an assortment of ships (Pelican, Longsword, Hornet, new vehicles [UNSC]) (Spirit, Seraph, Banshee, new vehicles [Covenant]). You can either:
1. Fly into the hangar and destroy key points of the ship.
2. Stay and defend your ship (turret emplacements are operable).
3. Dogfight.
4. Destroy key points of the ship from the outside.
Once the other ship is destroyed, you win.
That's my to cents. Peace.
~Hunter