A decent proposal

 

It is quite clear that an invasion from Russia and Belarus is quite possible in the near future. When looking at boots on the ground, Ukraine will probably prevail against Russia and Belarus.

The problem is that most likely Ukraine will not be able to protect it's airspace against Russian air power. If Russia is allowed to use Ukraine's air space at their own discretion, then it's possible that Ukraine will loose a war against Russia.

How can Russian air dominance over Ukraine air space be avoided?

Well, there is actually a solution to this dilemma. In accordance with International Civil Aviation Organization rules it's quite clear that Ukraine owns the mandate tor regulate it's own airspace.

So what?

Ukraine can decide to create a no fly zone, let's say 5 kilometers within it's own border and only have a few flight corridors for civil aviation. All aircraft within the no fly zone that are not positively identified by Ukraine air traffic control will be shot without visual identification.

Of course Ukraine's air force will have a hard time to control the vast areas and cover them with their own air force. So, alas, why not a coalition of the willing, supporting Ukraine with combat aircraft with BVR capabilities? This would be a powerful signal to Russia that it's air force will not be able to roam the skies of Ukraine without penalty. There is no legal restrictions for a no fly zone and a coalition of the willing.

The main obstacle would of course be to identifiy which countries would take part in policing such a no fly zone, but as far as I can see, at least US and UK would be hard pressed not to participate, if for no other reason, but they are signatory states of the Budapest Memorandum of Security Assurances. 

Maybe that would be an incentive for other European states to support a no fly zone?

I can imagine that such a coalition of the willing with some major EU member states and USA would be a real deterrent for an invasion. The best part would be that the coalition don't have to be based in Ukraine, they could be based in Poland, Slovakia, Hungary, Romania, Bulgaria or Turkey.

Without air power over Ukraine, Russia can not win this war. Which of course is the main objective for a working deterrence.