This is an interesting discussion. Here is my twopenneth:
I always put my Iphone on silent when flying (I am a student pilot) so I do not annoy my FI if the phone rings. However, both my FI and I have bluetooth capability on the headsets and my FI has used his phone to contact airfields when out of radio range to check on VMC during one or two of my cross country flights.
It seems to me that the ability to use you phone from the cockpit in an emergency (Radio failure, for example) is a potential lifesaver.
I may have this wrong but I believe that Airbus, maker of the first totally FBW aircraft, did some tests and found there was no interference from mobile phones that affected aircraft systems.
I have just checked and it is correct that you can turn wifi and bluetooth back on in flight mode. looks like everyone is a winner!
