This morning two Turkish F-16 fighters shot down a Russian jet, claiming that it was in Turkey’s airspace after it had ignored repeated warnings.
There are two problems with this story. The first is that Russia claims to have evidence that the Russian jet never left Syrian airspace. The second is that even if the Russian jet had strayed into Turkish airspace, Turkey knew there was zero threat to its security from a single Russian jet. Everybody and their uncle knows what Russian jets are doing in the area.
This means that NATO, of which Turkey is a member, had given a greenlight to the idea of shooting down Russian planes.