^^ This.
Every airline in N. America asks that you turn off GPS receivers during flight. That is different than saying there is a demonstrated EMI issue, but they get to make the call.
Regarding cell phones the major barrier to their use on board is the FCC ban on their use while airborne, not the FAA. This ban is based on the concern that the cellular device may use excessive network capacity by emitting a strong enough signal to communicate with multiple towers simultaneously. Mobile protocols will resolve which tower the phone will attach to, but theoretically there could be a loss of some capacity on the network.
Outside the U.S. where such prohibitions don't exist companies such as OnAir and Aeromobile provide systems that enable GSM phones to be used in flight. One of the features of those systems is that they create an RF noise floor on the plane to ensure that the phone attaches to the on board pico-cell (essentially a low power cellular base station) and not a tower on the ground. The pico-cell then forces the phone into its lowest power mode. This was deemed necessary to protect the terrestrial cell carriers who own spectrum licenses that extend from sea level to outer space.
Back on the original topic, I did some playing with the airplane mode widget on my Droid, and it does not seem to disable the GPS. That may vary from phone to phone, and also based on the widget you use. In my case I'm using a third party widget, not something that came with the phone.
