This really looks like a stupid move by Turkey. According to their own map, the Russian jet went over a small protrusion of Turkish. territory, was clearly on the way out back to Syria, and was almost there (it seems clear the plane crashed in Syria). The Turkish pilots said they told the Russians to leave Turkish airspace, the Russians allegedly didn't respond, but since they were clearly on the way out, why not let them go?
It seems one of the Russian pilots was killed by gunfire (not captured alive) while parachuting down, the other pilot's whereabouts seems to be unknown. As Python noted, though, there is still some ambiguity about who and what brought the jet down, as the Russians last I heard were claiming it was someone on the ground. Frankly, when I first heard that, I almost wondered if they were giving Turkey a way out, by letting it appear it wasn't American's NATO ally that shot the jet down, but a rebel force in Syria.
Also of relevance here is Putin saying his meeting with Hollande will be the beginning of a coalition to fight ISIL. There is of course already a coalition. I can't believe how difficult it's proving for countries that ought to be 100% together against ISIL to work together. At a recent speech, Obama said getting rid of Assad wasn't just a moral issue, but a practical one, that given the opposition to him in Syria, there's no way he could remain in power even if the U.S. didn't oppose him. But that seems to ignore that he also has a lot of support in Syria, so it's not obvious that anyone else at this point could take over, either.