Can you use the iPhone GPS in flight on an airplane to track your position?

If so, do airlines allow it?

Answer
No. Wireless devices are banned in flight so there is not chance they interfere with flight equipment. You will need to shut off your iphone and keep it off until you land.

It depends on your airline. Some allow it and some do not.
You can check on the web site of the airline to see if they have a prohibition. If they do not list it, you can use it. It will need to be turned off during take off and landing when all electronics are to be turned off.

Reception of the GPS signals depends on the quality of the receiver and if you have a window seat. The airplane body will block the signal so you will need to have it near a window.The newer receivers do a better job of getting a lock in difficult signal locations.

you can use your iPhone in flight, as it has a flight mode. as for the gps in a iphone im not sure because a iphone uses cell towers aswell as gps. if you have a hiking style gps you cna actually use them after the seat belt sign is switched off because they aren't technically a transmitting device... but check with your airline first
I don't think you can get a signal whilst on a plane. And you don't stand a big chance of being allowed to do it anyway! :-)
I'm unsure if a airline allows it or not, but its highly unlikely to get a signal in a plane anyway.