Re: But does it need to break to create a risk?
"I think a no-fly zone within about 10 km of an airport would be something like reasonable. 100 km seems overly conservative."
In the US, it's 5nm or just under 10km. A problem is that when you look at a pilot's map, you quickly see that in many cities, there are only a few city blocks that aren't within 10km of an "airport" since "airport" includes helipads at hospitals, the roofs of large office buildings, fire service facilities, police heliports, etc. A real estate photographer showed a map of his service area in Florida with circles around each "airport" and it left very little legal space to fly without having to file a special notice in advance (NOTAM or NOtice To AirMen).