Which AEG carried a 20 mm cannon?

The 20 mm Becker Type M2 was not designed for light fighters. Its main users were large twin-engine aircraft, initially grouped in the Grossflugzeug category — "class G" — defined by IdFlieg, the German body responsible for classifying and overseeing aviation equipment. Two specific types head that list: the Friedrichshafen G.III bomber and the AEG G.IVk ground-attack aircraft. The underlying reason is one of design: a weapon of that calibre, with its ammunition, required an airframe with carrying capacity and room for the crew member serving it — something class G offered and a single-seater did not.

Within AEG's catalogue, the aircraft linked to the 20 mm cannon is therefore the G.IVk, a ground-attack derivative of the G.IV bomber. This was not a marginal branch of the manufacturer's output: the G.IV was the bomber of which 320 examples were built, so the armed variant started from an already established, mass-produced twin-engine airframe.

The resulting combination says a good deal about German aviation at the end of the First World War. Rather than designing a new aircraft around the weapon, a class G bomber was taken and adapted to carry the Becker Type M2 against ground targets. That is the G.IVk's role, and that is the answer to the question: the AEG that mounted a 20 mm cannon was the G.IVk, the G.IV's ground-attack sibling, alongside the Friedrichshafen G.III as the other major carrier of the same cannon.