"Cadet Training" Superman Sunday Newspaper Strip - March 28, 1943 to August 8, 1943
The Sunday strips are about to make a change from multi-episode, months-spanning stories to episodic adventures which wrap up in a week or two, with Cadet Training - where Superman must protect the Daily Planet’s “Model Air Cadet” from the schemes of Nazi agents seeking to break American morale - being the last lengthy arc for a while.
Why begin abbreviating the Sunday adventures? Well, beyond any editorial edict, America (and, in general, the world) is beginning to suffer a paper shortage, what with most vital materials earmarked for military needs or shipping off to the overseas Allies.
This paper shortage - and the subsequent paper drives which followed - contributes to the topography of comics history by seeing many comics of the Golden Age shipped off to the recyclers. The rarity of so many older comics - some of which sold literally millions of copies a month - can be attributed to the numbers of which were patriotically pulped for the war effort.
Likewise, the newspapers become more of a rarity, and many regular readers may have considered the Sunday paper a luxury in wartime, indulged in so infrequently that an ongoing story becomes a burden.