Let's remember, the airlines were about to allow cellphone calls during flights. They would have to install a cell tower, so to speak, in each aircraft to pick up your signal and transmit down to the earth towers. They were going to charge ~$1.00/minute. There was such a hue and cry from the public not to allow this, that for the time being it is a dead issue. So, the airline knows that there is no problem (European airlines do allow cellphones) with cellphones when there is a profit to be made. So if in fact cellphones are safe during flight, then gps is definately safe.