The use of a GPS device on an aircraft in-flight (or on the ground, if it comes to that) interests me. I have a small GPS which I have used on a flight back from Paris a few years ago, and I still have a copy of the 'track' flown from gate to gate. It only really works if you place it by the window, so that it can 'see' the satellites.
In March last year I was in the USA and did a little flight in Arizona. I asked the pilot if I could use my GPS during the flight, and he was quite happy with it. In fact, he suggested placing it on top of the instrument panel so that it would get a better signal. During the flight I asked the pilot about possible interference, and we moved the GPS around several times, trying to get a reading on any of the instruments. Nothing, nada, zip!
On long distance flights I get bored, so I like to look out of the window and look at various features on the ground below. Later, if I'm able, I try to find these things on Google Earth, to see what else I can find out about those places. Having a GPS makes it so much easier. I can record a location (or 'waypoint', or POI, in GPS terms) for later use.
I find that the moving map display on the 'in flight' entertainment system is completely useless, and nowhere near accurate enough for what I want to do.
As somebody suggested above, do you seriously expect me to go and knock on the cockpit door to ask the pilot for a lat/long readout?? How about if I do this every 30 minutes over the entire flight? How long do you think they would continue to answer the knocks on the door?
There is a product on the market which I have been considering. It is called a 'Trackstick'. It is a small GPS receiver with a memory; it can be programmed to record its location every 1 minute, or every 5 minutes, or every hour, or whatever. Later, the whole set of location recordings can be downloaded for later use or analysis. There's no display on a Trackstick, so you can't instantly see where you are.
So, with a suitable Trackstick placed next to the aircraft window, set to record its position every minute, if I see anything of interest on the ground below I just need to make a note of the time and what I saw, and when I download the data from the Trackstick I can match the two to see where I was.
Going back to my original comments - my GPS device is a small grey box about the size of a box of matches. It uses Bluetooth to communicate with my mobile phone. So, I set the phone to 'flight safe' (as allowed by the airline), and use a Bluetooth connection (also as allowed by the airline) ... what am I doing wrong?