Airline passengers must turn off devices but it’s not clear why

On his New York Times blog Bits, Nick Bilton wonders why we must turn off our mobile devices when we take a plane ride: "Let’s assume that just 1 percent of those passengers left a cellphone, e-reader or laptop turned on during takeoff or landing. That would mean seven million people on 11 million flights endangered the lives of their fellow passengers. Yet, in 2010, no crashes."