Scorpion
Glitches
In the Blood Gulch level with two tanks, there is a very entertaining glitch. You flip over one tank by driving it up the wall then jump out of it. It might take a few tries. One this is done, you take the other tank, and drive up over the flipped tank. You should now have one tank on top of the other. Now that this is done, either you, or a friend flips over the lower tank. The tank on top is launched all the way to the other end of the map.
Warthog
Banshee
In Halo 2, the Banshee's controls are much less realistic than they were in Halo: Combat Evolved (which operated like an airplane). However, it is much easier to aim and navigate in Halo 2. The Banshee has two plasma guns mounted on its nose which fire at about the same rate as a Plasma Rifle. While firing the Banshee, speed is temporarily limited. Ordinarily, the vehicle is very slow and a very easy target to Rocket Launcher fire, but the Banshee also come equipped with two thrusting mechanisms, one on each wing. When activated, the Banshee's speed doubles, but turning and aiming becomes more difficult. The biggest drawback to the thrusters is the fact that the plasma turrets cannot be fired while boosting. The thrusters can also be used for barrel roll moves, which makes the vehicle capable of rolling upside down from side-to-side, and elevate higher.
Ghost
Wraith
The Wraith is the standard tank vehicle for the Covenant. During campaign missions, it is impossible to enter one, oddly enough. It can fire long-ranged plasma rocket-type things which has a pretty decent kill radius. To take one out, whip out your Rocket Launcher and fire a couple shots at it. Or, if you don't have one, get in a Banshee or Ghost and start firing madly at it. If you don't have any of these, then RUN LIKE HELL.
Or, if you are close enough, jump onto the tank, and it will tell you to melee the hatch open, then place a grenade in it to blow the driver out. After that, you basically own the vehicle, provided that no other Covenant is in the area to retake it.
Spectre
This vehicle is basically a Covenant Warthog, but the passengers are more exposed, and there can be 2 passengers instead of one
Turrets
Human
The human turret is a very efficent weapon, with a quick rate of fire and almost no recoil. It is very valuable for base defense. A turret may have a bit of trouble with shielded targets, but once shields are eliminated, a turret can kill in less than a second.