JF Ptak Science Books Post 1688 (Part of the series on the History of Blank, Empty and Missing Things--Upper Atmosphere Monsters.)
Illustrated World for July-August 1920 asks the question "Will Man Soar to Unknown Heights" and indeed, they answered in the affirmative, saying that the "heights of space instead if the depths of the seas or the distant poles are to beckon the adventurous, according to scientists who are making a specialty of the atmosphere". In what must seem to the modern reader to be an enormous and naive statement of the obvious, the future aviators would fly in "glass enclosed fuselages" in order to gain great heights.
There would however be no monsters--except for lack of oxygen and the cold. he editors did mention a Conan Doyle story in which monsters lived at high altitudes, monsters that were form-changers, much like the clouds they lived above. This was his "The Horror of the Heights"(1913), a short story about a flyer named Joyce-Armstrong who longed for great heights--and for the "something else" that was up there, something dark and sinister that lived in the stuff that we breathe, as the story is told through the pages of a recovered, blood-stained notebook found in a field. We learn that Joyce-Armstrong was a dreaming pragmatist, longing for the ethereal of great heights but loathe of it also, aware of a danger so great that he carried a shotgun along with him in flight. We read in the flight book that the aviator had an experience at 40,000 feet, meeting a new air-jungle world of semi-formed gelatinous creatures, one of which has a more solid form with tentacles and a beak, and does battle with them, surviving, returning to the ground. He vows to go back, at which point we assume he met his doom.
In 1913, an altitude of 40,000 feet was extreme, the record at the time being about 9,000', and that reached in a Wright biplane--quite an achievement I think for such an aircraft, By the time this article appeared in 1920, the record altitude was 33,000', which at least got a lot closer than the 9k' of 1913. The aircraft for this record--the LUSAC-11 (Lepère United States Army Combat) was much more considerable than the Wright plane, though it seems to me a work of fantastic skill/effort/courage to take such a thing so high.