Covenant air artillery
From Halopedia, the Halo wiki
The Covenant Air Artillery is an airborne vehicle armed with three Plasma Mortars (the main armament of the Wraith) and its a sort of airborne seige vehicle for raining plasma down upon UNSC bases and destroying them. As it has no on board defenses, it can be very vulnerable if dealt with promptly. However, its heavy plasma mortar cannons can lay waste to an entire UNSC base.[1]