[gordner]

Carriers that allow cell use on board aircraft in cruise are using repeater systems mounted in the cabin roof. With that system, all the phones will broadcast at their weakest setting as the "tower" is in proximity to the phone. At that level the phones are safe for use on an aircraft. Without the repeater, every phone looking for a signal will transmit at the full power setting, not a big deal for an individual phone or two, but a big deal if there are 200 of them.