This latest information obviously works against possibilities that the plane vanished from radar coverage because it blew up -- via bomb, some structural failure, missile strike, meteorite, what have you. The fact that the plane kept flying, with its transponders turned off, also works against any "pilot hypoxia" assumptions. (The idea that the pilots somehow both lost their oxygen supply and passed out, as happened in different circumstances 15 years ago in the Payne Stewart crash and in a crash in Greece in 2005.) If two pilots were simultaneously nodding off at the controls, there is no reason why their last conscious act would be to disable the transponders -- rather than radioing for help, descending into thicker air, reaching for the emergency oxygen bottles, etc. Possibilities involving deliberate destruction -- by the flight crew on its own, or by attackers who got control of the plane -- thus become more likely.