On the first mission (Hale's Gambit) you pilot a flying vehicle. The controls are the same as the flying vehicle from the main campaign. For this achievement, you need to kill all of the Red Faction on the exterior of the base. As you fly along, watch you radar for red dots to see where the Red Faction are. If you're having trouble finding them, press to highlight them in thermal imaging. The final Red Faction you need to kill are around a generator that you need to destroy, before you infiltrate the inner defenses.