You can only unlock the area flight restriction if you can connect to wi-fi or receive a cell phone text with a code. If you're out of mobile data range or wi-fi then you're SOL. I learned to unlock my P4A+ before leaving home, while I still have wi-fi, since my home is in the same restricted area, close to a rural airport with 0-6 small plane flights per day. l can't even take off in my living room because of it. There's a way to do an advanced unlock of a restricted area before you go there, but I haven't learned how to do it. If you're really close to an airport then DJI Go won't even let you take off without an unlock. If you're further away it will let you take off, but then pops a warning that without an unlock your drone won't fly toward a restricted area during automatic return to home. For me that means if I lose control signal while over the ocean, the drone won't come home, but will only hover in place until the battery is too weak, and then it will auto land in the oean. Bye-bye aircraft. It sucks.