I have a friend who's a pilot for one of the major commercial airlines. He uses his iPhone during flights all the time (seems to be common among pilots). I guess only the passengers are subject to the regulations. Though, I do realize that the pilots can easily turn theirs off if there's an issue; it's a little harder to track down the phone causing problems if it's one of the passengers'.

Regardless, the data doesn't seem to concretely prove that phones are causing any of the problems