Night Raider

I have never had a problem with a GPS in my carry on or using it in flight (on Air Canada). I am a pilot myself and there is nothing a hand held GPSr does that will effect anything on the airplane. Back before panel mounted GPS were standard in airliners some pilots would bring a handheld GPSr with them on their flights. So there isn't really anything wrong with using a GPSr in flight but you might get a flight attendant that doesn't know what it is or just wants to enforce/make up rules.