M651 missile launcher
From Halopedia, the Halo wiki
The Class-2 Guided Munition Launch System[1] is a United Nations Space Command aerial vehicle-mounted weapon system.
The Hornet is equipped with two of these weapons, and each weapon system is believed to encompass a lock-on targeting missile launcher and a tri-barreled chain gun. It can be customized to fire armor-piercing missiles at a very high rate, or also fire high explosive missiles similar to a Banshee's Fuel Rod bomb. The missiles have a limited homing ability on enemy vehicles and explode after a certain amount of time being in the air.[2].
