I always travel with my GPS (it is also my CellPhone) and have had no problems thru security. And to using on AA, I have not yet done it (did on AS with no prob, but before 9-11) but on the GPS newsgroup they said to ask the Captain or FO or even a FA. Most find it interesting and if they are not overwhelmed they might allow it. Never hurts to ask, but be sure to ASK First, so as to not cause an unplanned security incident.