"Air superiority achieved by a small air force over a nonexistent one does not mean the small air force in possession of
air superiority therefore has enough assets to influence large land campaigns."
True, but a modern nation that has enough resources to build an army large enough to participate in a 'large land campaign'
should have enough resources to build a comparably large air force too.
The only constraint would be if the nation (note that I wrote 'modern nation') was too technologically backward to develop
its own air power, but, if that was the case, it likely could purchase aircraft from abroad.
The Ostfront (1941-1945) was vast in scope. Looking superficially, one could argue that the Luftwaffe's force-to-space ratio
was too small--even when the Luftwaffe enjoyed air superiority in 1941-42--to be much of a factor in the land battles.
But the Luftwaffe did not spread itself thin, blindly assigning the same numbers of aircraft to the active and quiet sectors alike.
The Luftwaffe preferred to concentrate itself, when practicable, in the most important sectors at the time.
So, though outnumbered, the Luftwaffe could achieve air superiority, albeit fiercely contested, at the Battle of Kursk in 1943.
In striving to relieve the siege of Leningrad in 1943, a VVS air army was deployed in support of RKKA.
For some months in 1943, a single group of JG-54 had the primary mission of denying air superiority to the VVS.
This well-experienced group had at least several exceptional fighter pilots (Nowotny, Rudorffer, Lang, etc.).
Walter Nowotny alone was credited with shooting down about 167 aircraft in a period of four to five months.
It's rare that an individual combatant can do so much that he had an almost strategic effect on the campaign.
The RKKA did not succeed in completely breaking the siege of Leningrad until 1944.
