There are plenty of rules that passengers have to abide by if they're traveling by flight. But in this NY Times interview, pilot Patrick Smith thinks we should all perhaps chill out a bit about barring cell phones from being used. He says:
“I’d venture to guess at least half of all phones, whether inadvertently or out of laziness, are left on during flight. If indeed this was a recipe for disaster, I think we’d have more evidence by now.”
But that doesn't mean all devices are good to go. Things like tablets and laptops should probably still be stowed away only to avoid them from accidentally decapitating you during massive turbulence. Find out more by reading the rest of the interview here.