To me, the most interesting thing about all of this is that civilian airports don't really have radar. You can disappear from an ATC screen just by turning off a transponder. If they'd had radar we would at least of known which way the plane went. A curious controller could have asked "unidentified object at height X, region Y" who they were and why they were in controlled airspace without a transponder on.
The article even implies the controllers themselves did not know this:
>Initially, no one noticed the sudden disappearance of the airplane. After handing the flight over to Ho Chi Minh control, the Malaysian controller looked away from his screen, and when he looked back, the plane was gone. He assumed that it had flown out of radar range and returned to his duties without a second thought.
But there was no radar range limit. There was only a transponder range limit (or more likely an edge of the screen).
>In Vietnam, controllers expected the plane to contact them, but it did not, and they couldn’t find it on radar either. Controllers in Ho Chi Minh City began trying to raise the plane on radio without success. For 18 minutes, they sent out a series of increasingly desperate calls: would MH370 please respond? Could any planes in the area contact MH370? The only answer was silence.
So even when they were actively looking for it, it was invisible to their "radar". True radar would have told them there was a plane-sized metal object in their airspace even if it refused radio contact and had no transponder...
It turns out you can make an entire plane full of people completely invisible by throwing 1 switch. Who knew?