From 1940 on, the air was viewed as a decisive theater of war. Military men spoke of ‘air superiority,’ ‘air supremacy,’ or ‘command of the skies.’

From 1940 viewed by whom?

I am looking at the survey of foreign military thought in “War and Revolution” 1927/09, specifically article “Combat application of air fleet and anti-air artillery” by Piorun. From the experience of Polish-Soviet war, naturally.

https://archive.org/details/voina-i-revoliutsiia-1927-09-12/Vo?na_i_revoli?u?t?s?ii?a?_1927_09/page/141/mode/1up

The first part is “Air Offense”. The first paragraph starts with «The future war will definitely be of maneuver.[1]» [1: reference to “Application of aviation in fighting the cavalry” by Gen.Staff Major Steblovski] and the rest leads to the second, which starts with «Poland must by all means and thoroughly prepare to parry all attempts of the adversary to seize the air. Only full possession of the air will make possible free, not dictated by the adversary, decision making in regard of the ground forces.[4]» [4: reference to “Aviation of the world war period” by Gen.Staff Major Kvetsinski] etc etc. Then 5 pages of details on interaction, early warning, and so forth.

As a side note, he worried much about chemical weapons delivered by air, and so did his Soviet contemporaries, as seen in the same journal. Of course, in the next 10 years not only everyone and their dogs were issued a gas mask, but bomber payloads increased.

40 mm anti-aircraft artillery used in the ground-support role firing rounds with proximity fuzes won the Battle of the Bulge.