GPS does work on airplanes! Google Maps on the S5 requires an Internet connection to load maps as you move. If you are to purchase a 3rd party Navigation app like Sygic or TomTom which allows offline use of maps then you will be able to use GPS on a plane.
Last Summer, I took photos through the plane window with my S4 while flying over Greenland and to my surprise the images were geo tagged and showed my exact location on a map.
Wow, that's deep man.
But, I think you need a data connection to load the maps.
There are apps out there that will allow you to gps yourself on a flight using offline maps.