I've flown several times with both a handheld gps and transceiver. The first time I had a need for them at my destination and was a bit concerned about having them taken away, so I packed part in my carry-on and part in my suitcase...no one said a word. The next trip was to Canada, which included a helicopter ride, so I hoped to use it during the layover and possibly during the heli-leg. I was too concerned about causing a stir on the way there, but on the return, I asked a security agent and the helicopter pilot, both of whom said 'no problem' and the latter even pointed out some of the local frequencies while we were flying. During the layover before our trip home, I became chatty with a pilot, who was deadheading on our flight. He was eager to play around with the pilots and used the transciever while the cabin door was open. I was surprised by how open he was about everything, even if it was legal to use, I thought there should be some discretion as to not worry the other passengers. This was in Vancouver, so perhaps it would be a different scenario in the US. I've since flown with my handheld and have not used it again.