I've noticed that the size of no fly zones vary depending on where you look. The DJI website showing the smallest no fly zone. I believe there was also something on their site about R1 and R2 zones. Next on the list is UAV forecast which shows a 4 mile NFZ around the local airport (JST, Class D). Looking up class D on Wikipedia it also says 4 miles. UAV also shows a 1 mile NFZ around the hospital heliport. Then you have Know Before You Fly/AirMap which shows a 5 mile NFZ (this the one I've going by). Last you have the B4UFly app which shows a slightly larger NFZ when the app chooses to work which isn't often. It's NFZ is about a half mile larger than Airmap. On a related note when you wish to fly within a NFZ you are to notify the airport/ATC but the only number listed is for the airport manager. He doesn't answer his phone or respond to emails.