As far as motive is concerned what about this?
"Friday, 28 March 2014
The disappearance of four members of a patent semiconductor traveling on Malaysia Airlines MH370 makes the famous billionaire Jacob Rothschild the sole owner of a very important patent.
This report has caught legs across dozens of European based news outlets. Did Rothschild exploited the airlines to gain full Patent Rights of an incredible KL-03 micro-chip? According to the reports, Jacob Rothschild is dubbed as the "evil master plotter".
Taken from the previous link i posted.
It's unlikely with the black box, satellites, etc all of the technology at their disposal there isn't a trace.
Just seems suspicious. This Rothschild benefiting could just be a coincidence.
Nevertheless something to ponder before dismissing the incident.