Immobile, towering, wall-linking. Deadly against anything that flies. Cannot attack ground units, especially deadly anti-structure vehicles. The Flak (Fliegerabwehrkanone) is the Forgotten anti-aircraft defensive structure in Tiberium Alliances. It spawns in 20+ camps although, rarely in level > 18 camps. Dangerous against all forms of aircraft. It should be noted that it counts as a structure and anti-structure ground vehicles/infantry can demolish these quickly. Firehawks and Vertigoes can down these quickly, as long as the Flak dosen't get them first.