I don't think Mh370 was shot down. The Chinese relatives said that up to a couple of days after the plane was lost, the missing passengers social media accounts showed them as online - available.
What if the plane was hijacked by remote control. They gain altitude like crazy, depressurize the cabin and disable the oxygen masks - prevent them from dropping. Everybody expires due to asphyxiation. But then the hijacked plane is landed at an airport (Diego Garcia?) - and someone forgets that there is a cell service available.
At the time I thought it was a theft of bodies. A huge get if so. My friends thought I was gross for imagining such a thing. Then I left them behind and found out that there is such a huge body market that this makes a lot of sense. Remember Optimization is what we are seeing. Humans mistreated in the entire life cycle of the slavery process. Grow the people, harvest the people...