Russians have made several efforts in order to control the Ukrainian airspace but the effors seems to be defeated and I believe it would only get worse since the Ukrainians are really begining to get up to speed with various modern NATO surface-to-air missiles(SAMS )...
I think that strategically the Russian military would not want to or cannot be able to risk its fighters incase of an incoming conflict with NATO and of course that is becoming more probable , they cannot engage in a war with NATO without their fighters because such war will be over even before it began..What that means is that the only option which is available for the Russian commanders is the nuclear...
Another question is that does Russia have the industrial capability to be able to actually replace all the planes they have lost??NO they do not have right now in my opinion...And going to a war with NATO , I am sure the NATO commanders would be smart enough to target the aircraft manufacturing industry and also the hi tech industry which would of course happen after they might have gained the air superiority..
Let's look at it from the economic angle, economically it seems that russia cannot presently afford to replace their fighter jets if they loose them and that is why they might be careful of the way they use the fighter jets because if they lose it then it becomes a bigger problem for them...
Well it seems that the Russian commanders would only be left with a kind of nuclear option if they want to go into war with NATO..
