There are two theories out there about shooting down aircraft.
Alfred Lambremont Webre says the Ukrainian Wiki Leaks released a document on October 28th saying McCain (McInsane) & some guy from Georgia were involved in a plot to shoot down an American plane in Syria so Russia would be blamed for it. And shooting down a Russian plane so America would be blamed for it to start WWIII. Two days later, Russian flight 9268 Metrojet Airbus 321 crashed. Lots more details in the interview and article below.
The other theory says US and Russia governments agree an Israeli F16 jet fighter flying out of Ramon Air force base shot down the Russian airliner. Possible Russian attacks on Israel, according to this theory.
So you pick which theory you think is right, or if neither is. There's probably more theories out there too.