FlyoverGPS

FlyoverGPS is an offline (or online) mapping app that allows caching of OpenStreetMaps, Nokia Satellite or Google Maps Tiles for offline viewing, as in "Airplane Mode" without a Network connection.  It displays a flyover map of your plane's location when in flight if your device hardware is capable of getting a GPS fix while in the air.   It is optimized for airline passenger use when flying, also displaying

-speed
-altitude
-heading

in english or metric units, or can be configured to display heading in compass degrees or speed in knots. This app can also be used to cache maps for offline use in any travel situation, or is perfectly capable of displaying your position and direction with a network connection.

GPSTest included, as GPS fixes in an airplane without benefit of network triangulation can be problematic.  The best results that have been reported involve a southern exposure window seat, although newer phones seem to be much better at achieving a GPS fix than older ones.  I would be interested in comments documenting this behavior.

Finally, be aware that while most airlines do expressly allow GPS receivers to be used during the cruise portion of the flight, some do not.  The in-flight use of electronic devices is always subject to the final decision of the Captain and Flight crew.