200+ passengers sitting in the back with mobile devices.
Now surely instinct these days is to grab for your mobile first - maybe even video the event! So it just appears odd that there is not a single piece of mobile transmission evidence appearing. A "ghost" plane with the pilots knocked out behind a security door run on autopilot would surely have every device owned by anyone still conscious at back on speed dial. Even in a hypoxia situation, then surely at least one phone would have been switched on by someone in distress and stayed on for the remaining time of flight.
Our former tv weather and science guy wrote a good explanation of why cells don't work from the air. It's here:
Why Cell Phones Don?t Work (Well) From The Air ? My Permanent Record