Halo 4's first DLC map-pack, Crimson, lands on December the 10th, bringing three new multiplayer maps and eight new Achievements. The details of the latter have just dropped via Halo Waypoint. Better polish up that aeriel combat if you want them though. Jumping seems to play a rather large part.
The details? As below.
Now They Fly?
Get a kill while airborne in a Warthog - 50 points
Size Is Everything
Kill 20 enemies with a detached Machine Gun Turret - 20 points
Kill a player while you're airborne from using a Man Cannon - 30 points
Kill 20 enemies using the Mantis' stomp attack - 20 points
David and Goliath
Board an enemy Mantis - 20 points
Shoot an enemy out of the air while they use the Man Cannon - 40 points
Kill an enemy with a melee attack when landing from a Man Cannon - 30 points
Pump Yer Brakes
Score the killing blow on a Mantis - 40 points
As for those maps? All the details (as well as a whole raft of screenshots) are right here.