I would like to be able to use my Garmin etrex (that my wife uses for geocaching) in the air. I noticed however, when I go to Airnav.com that the coordinates for airports are listed in 3 different ways and all with way too many numbers after the decimal to fit on my GPS. I also haven't tried this gps yet in the air, but it does have WAAS. Of course, it doesn't have moving map or anything like that, but it does show direction, heading etc and distance to point or waypoint. Does anyone know anything about why the airports don't use normal coordinates? Would like to avoid buying a Garmin Aero 500, but maybe I will need to?