Joint Operations
I feel that there are at least two different threads going through here.
Firstly the right of any country to defend its own airspace and secondly the agreed primary target for all the air forces in the region ISIS, except possibly the Turkish air force that has the Kurds as its primary target we are lead to believe.
I have heard no discussion of the Syrian State asking the coalition not to invade its air space and bomb ISIS targets, I have heard of Turkey issuing Diplomatic Messages etc to the Russians about not entering their airspace.
It cannot be too difficult for the Russians to understand that if they bomb a Turkish backed group just to the south of the border using a type of plane that the Syrian air force has, remember many of the Russian planes in photos have had their markings removed, that if they cross the border they are in danger of lethal force being used, the Syrians did shoot down an F4 for a slightly similar infringement.
As for all of the coalition targeting ISIS, I would have thought by now that there were rather fewer targets available than a few months ago. Do all parties engaged in the campaign have the same definition of what at ISIS target actually is? Assuming hat the Russian Cruise Missiles used the other week actually hit ISIS targets, was there any prior warning of these targets, to avert the possibility of two attacks at the same time on the same target?