Making an aircraft disappear might have taken Ukraine off a few front pages, but the propaganda benefit to Russia was - as any reasonable person would have anticipated - minimal at best. It made essentially no difference to Western policy towards Russia, and if anything drew a bit more attention towards crashes involving Malaysian Airlines 777s than was good for Russian interests.

Conversely, the implications of being caught hijacking an aircraft full of civilians and flying it into their own airspace would have been very severe indeed, especially given the number of citizens of their neighbour and only major international ally on board.

Consider the reward is minimal at best, the cost of failure is exceptionally high, and the probability of failing to hijack and fly an aircraft several thousand miles over multiple jurisdictions without detection is comfortably above zero.

Assume that anyone with the acumen to pull this sort of stunt off successfully possesses the faculties to do some basic weighing up of risk and reward an ask yourself why on earth would they do something so risky for such a trivially achieved and insignificant objective as distracting news media

Just because a particular organization theoretically could pull off a particular course of action doesn't mean it's not ridiculous in the extreme to assume they would.