The wikipedia article is more interesting: http://en.wikipedia.org/wiki/Mobile_phones_on_aircraft http://en.wikipedia.org/wiki/Mobile_phones_on_aircraft This s

The wikipedia article is more interesting: http://en.wikipedia.org/wiki/Mobile_phones_on_aircraft http://en.wikipedia.org/wiki/Mobile_phones_on_aircraft This sums it up pretty well: "The regulatory agencies and aviation industry take the position that any increased risk is unacceptable if it is avoidable." There's some technical channel sharing problems where phones have access to more towers than designed on land. The FCC can't predict what would happen if phones were allowed to stay on in regards to cell roaming. They also don't know the effects on the avionics. It looks like they're developing 'picocells' to have an on-board tower, but there are struggles with the different cellular bands. Though, there are some European carriers that have been successful with just letting people keep their phones on. That said - I think if your device doesn't have a radio on it, it should be allowed to stay on. Which probably won't fly given the 'if it's avoidable' rationale.