I was on an American Airlines flight this week.  I was half dozing as the Flight Attendant went through the list of banned electronic devices (radios, ceel phones, etc.), but my ears perked up when she ended the list with GPS devices.  I'm sure I'm never heard them specifically listed before.  I got out their magazine and looked up the list in the information section.  Sure enough, GPS devices were in the banned list.  I don't know if this is a new policy or not, but I've used mine Garmin Etrex Vista on flights for the past couple years and was never questioned.  I was on three other flights after that one this week and the attendants didn't not mention GPS devices.