A unofficial Russian no-fly zone over Novorussia?

My friend "J" just sent me this most interesting video where a Novorussian solider describes how some unidentified aircraft apparently engage Ukie fighters and bombers and, in one instance, box them in and force them to land.  This is the first and only time I have ever heard of such a thing taking place, and I obviously cannot vouch for the accuracy of this soldier's interpretation for what he saw.  Does that appear plausible?  Well, think about it this way:

1) The Ukies have clearly lost control over the Novorussian airspace.  Not only they not have the means to control it by force, they probably are blind to what is taking place there.
2) While US SIGINT might be able to detect Russian aircraft in Novorussian airspace, they would have a hard time backing up that claim without compromising their sacrosanct means and methods.  Besides, considering the short distances involved the Russian aircraft could fly what is called a "low-low-low mission profile" and remain pretty much undetectable.
3)  If a Russian Air Force aircraft shot down a Ukie, everybody could credit the air defenses anyway and challenge anybody to prove otherwise.

So I would rate this source (the solider) as an 'unknown' but this story as 'credible but uncorroborated'.

Still, that would explain the heavy Ukie aircraft losses, would it not?

Cheers,

The Saker

PS: notice, by the way, how this solider repeatedly makes references to WWII and to the Nazis!  So - please - don't come and tell me that I am the one constantly using references to topics which every Russian knows are the crucial context in which today's events should be understood.