I suspect part of the reason passengers have to turn off their cellphones, and iPods for that matter, is simply that the flight attendant union (Association of Flight Attendants -CWA) wants to have some power over flyers. I mean, why do you have to turn off your iPod? Makes no sense.
NYT: Cellphones at 35,000 Feet?:and this is the other reason: flight rage.
Federal regulators plan next week to begin considering rules that would end the official ban on cellphone use in commercial flights.... Technical challenges and safety questions remain. But if the ban is lifted, one of the last cocoons of relative social silence would disappear, forcing strangers to work out the rough etiquette of involuntary eavesdropping in a confined space.
"For some people, the idea of being able to pick up their phone is going to be liberating; for some it's going to drive them crazy," said Addison Schonland, a travel industry consultant at the Innovation Analysis Group in La Jolla, Calif. "Can you imagine 200 people having a conversation at once? There's going to be a big market for noise-canceling headphones."
