Teardowns I've Worked On
Answer to: Why can't I receive GPS position when in Plane ModeYou can get a GPS fix in flight mode. The chances are that you're trying to get a location inside a plane which will block the GPS fix (as planes act like Faraday cages. Nothing in the iPhone's software actually prevents you getting a fix. The chances are, if you get a GPS lock outside the aircraft, then keep it next to the window while in filght, that it will maintain a GPS lock OK (getting a lock is harder for a GPS than maintaining one it already has). Therefore Alan's answer is not correct.