"the pings were another aircradt (eg a US drone)"
The pings have a signature, I believe, so said drone would have to have a replication of the equipment on the plane, meaning it was a pre-arranged plan ie not in response to the hijacking. Plus drones don't have anything like the range this would require. Plus the US doesn't have any bases etc in drone range, I believe. Plus there's lots of oil in the sea.
So no, I don't think that theory works.