A few of my friends asked how we can so easily track mobile phones but a jumbo jet like Malaysia Airlines Flight 370 can disappear without a trace. First off, one of these is designed to transmit all the time, but aside from that difference it is a big ocean out there and it’s still possible to lose things in it.
I responded to my friends with this:
Radars don’t reach everywhere. Polar-orbiting satellites scan the globe but are not always around. Mobile phones have a hard enough time connecting to a tower when turned on in a plane at the terminal. Over the ocean? Forget it.