Turks claim it violated airspace, ignored radio warnings to turn back. Russians and Syrians have been asked for months to avoid flying within 20 km of Turkish/Syrian Border.

http://www.bbc.com/news/world-middle-east-34907983

We need to tear up all of our treaties or we are going to get sucked into a world war to defend the Turks. I'm not willing to let my son die to defend Turkey.

Probably won't a lot come of it though. Turks are preoccupied with Kurds and Syrian refugees while Russia preoccupied with Syria and Crimea, etc. I bet those pilots will listen next time though.