美國很多 no-fly zones and Temporary Flight Restrictions；飛無人機需要用

The B4UFLY app,

created by theFederal Aviation Administration (FAA), isa free service that helps recreational drone flyers determine where they can and cannot fly.It provides information on airspace restrictions,TFRs,and other factors that could affect drone flights.

https://www.faa.gov/uas/getting_started/b4ufly#:~:text=The%20FAAs%20B4UFLY%20service%20shows,through%20desktop%20and%20mobile%20applications.