iPhone -- shutting off cell service, but not gps Airplane mode turns off GPS service as well as cell service.  Is this necessary under the new rules allowing most devices (at least on some airlines) to be used during all phases of flight?

If it's not necessary, is there a way to turn off cell service while leaving the GPS system functioning?
With my experience, being 30,000 feet above earth and traveling at around 500mph, the GPS has a very hard time finding my location. Even if it does find my location, the map itself doesn't load due to a lack of cellular data. 

However, you can always manually turn off wifi, bluetooth, cellular data, and leave location services on.