Air Destroyers were large capital airships used by both the Anti-Traction League and its successor state—the Green Storm. They were capable of attacking Traction cities, being armed with great batteries of rockets and an anti-city cannon, and were powered by large engine pods. As military airships, their gondolas were armoured and fitted with gun ports.
During the events of Mortal Engines, they formed the core of the Northern Air-Fleet based at the Shield Wall in Batmunkh Gompa. During a clandestine mission to Gompa, London agent Thaddeus Valentine destroyed several Air-Destroyers; effectively destroying the Northern Air Fleet.
During the Green Storm's war against the traction cities, the Green Storm deployed them on many campaigns. The Requiem Vortex was the flagship of their leader the Stalker Fang. During the Battle of Brighton, the Stalker Fang and General Naga led a Green Storm Aerial Attack Unit consisting of four Air-Destroyers. In the subsequent fighting, two destroyers Sword Flourished In Understandable Pique and the Autumn Rain From The Heavenly Mountains were destroyed.