I've personally tried using GSM phones on several different aircrafts, including the Russian TU-154, Boeing 737, Boeing 777 - nothing out of the ordinary ever took place on these flights - in fact, on the TU-154 I had 1/2 range 3 minutes into the flight!

Here's a simple thing for airlines to do if there scare of phones etc is genuine - install a GSM jammer, so we can't use the phone. My phone doesnt have flight mode, but has an MP3 player, camera and video player that I'd like to use whenever I want.