When military aircraft are approaching international borders, they're warned that they're about to enter restricted airspace if they don't change course and warning them what will happen if they do. The Turks wouldn't have to enter Syrian airspace to intercept. Their air-to-air weapons have enough range to do it from within Turkey.
If they're going to attack targets in that area, they should probably be using standoff missiles that prevent the need for aircraft to cross into Turkey. It would allow them to fire it and then turn back while it still goes on to whatever target they have. Not sure how good the Russian weapons are though or if they've been updated since the Soviets.
I might be reading the radar map the Turkish government released, but the entire area looks like an absolute mess regarding airspace.
It looks to me, and this could be wrong, that the bit of airspace in question is literally a finger of airspace that juts into Syrian airspace. It looks like its a couple of miles wide at its broadest.
We also have been told that the Russian plane was under attack from the ground. The entire incident is idiotic and we should really be looking at what Turkey is up to over there. Turkey claims it warned the pilots as many as 10 times in the 5 minutes leading up to the alleged violation. The plane they claim was in Turkish airspace for 17 seconds. I don't know if this is the entire duration including the crashing, or up to the point where the Russian plane was shot. Either way, the plane crashed in Syria and both pilots landed in Syria. The plane was imminently returning to Syrian airspace.
The Russians have also claimed that the Turkish F-16's violated Syrian airspace in their attack. Looking at the radar profile it's not really hard to see how that is possible. I don't know the turning radius of an F-16 flying at combat speeds but I wouldn't be shocked if they entered Syrian airspace while turning in that narrow spit of Turkish airspace.
The real issue here IMO is, what exactly is Turkey trying to do. We're supposed to be on the same side in Syria. We're supposed to be fighting radical islamist militant groups like ISIS, Al-Nursa and others. Why would they risk provoking Russia in this manner? This had to be absolutely pre-meditated like they had orders to fire the very second Russian planes crossed the magic line. Even when the Russian planes posed no strategic threat to Turkey, or a tactical threat to any Turkish citizens.
So is this about which rebel groups each side is allowed to attack? The Turkomen tribes are clearly the proxy asset of Turkey.
The fact is, Russia is still a first rate military power, China, the United States and Russia are the three leading global military powers. The European powers that could potentially rival Russia are all largely demilitarized. Besides that, Russia and China are the only two military powers on Earth that devalue life enough to the point where they would actually pose a credible threat to western military power. In a vacuum they pose no credible threat, but when you combine two very important factors, general capability, and casualty tolerance, this changes things.
I'd say straight up, that the USA, Great Britain, Germany, France, whomever would not defeat Russia or China in a conventional non-existential war. For the simple reason they would be willing to take casualties we in the west would not be willing to over something that didn't threaten our way of life. Realistically the west could win easily, yet at significant cost, that is the point I am trying to make. It's not a price we would be willing to pay over this. This might seem absurd to you, but the question you need to ask is, how bloody would Russia make us, and would we be willing to pay that price over something as stupid as Turkey flexing its muscles?
European and American way of life is not threatened by it, our tolerance for casualties would be minimal, and Russia has the manpower, hardware and know-how to inflict casualties.
Russia is still geared to fight grand wars. The West has retooled entirely to fight high intensity, low duration conflicts against insurgents, or tiny insignificant rogue states. We have done this to minimize casualties because our societies simply do not have the stomach for casualties if the cause isn't worthy.
Do we believe for even one minute that the American public would rally behind Turkey as a worthy cause willing to lose hundreds of thousands of men to in a limited conventional war?
This is all a tremendous whatif, I doubt anything significant will come of this, but the idea of dismissing the Russians as little more than Iraq is silly. Not every war is an in it to the death struggle, and that is even more true for western democracies. We fight wars of limited scope to limit the casualties and damages caused. A war between Turkey and Russia and potentially NATO would be fought from the Russian point of view as though it were existential. They might not be the biggest dog in the fight. The toughest dog in the fight, but they'd be willing to die by the millions to win it, I'd bet on that. Would we?