I am "only"a frequent flier (Delta Platinum) and by no means an official source, but it's my understanding there is NO FAA rule regarding devices that might emit RF radiation. Try "google site:faa.gov bluetooth" and see what shows up. The ironclad rule is that you have to do as you're told by the crew (and if you don't, you can be arrested for that). The airlines make their own policy decisions and you have to obey them. I have not seen any specific references to Bluetooth in any "back of the magazine" policy documents on airlines I've flown recently. I've heard that British Airways specifically OKs Bluetooth but can't verify that. Boeing has been trying to peddle wi-fi in aircraft for some time. Apparently the satellite link part is pretty expensive.
