Flying turret glitch
From Halopedia, the Halo wiki
The Flying turret glitch is a glitch present in Halo 3 and Halo 4.
Walkthrough
The flying turret glitch can be done the same way in both Halo 3 and Halo 4 in the same way. First, start a Forge game with 2 players, locally or via Xbox Live. Then place a machine gun turret, a plasma cannon turret, or in Halo 4 a shade turret. We will be referencing the player in Edit mode as Player A and the player on a turret as Player B. Player B must start using the turret, then Player A must pick it up. Then Player B can fly in the sky with the turret.