At present, the Class G airspace up to 700 or 1200 feet ( above ground level ) is pretty much do-as-you-please in the USA outside restricted or prohibited areas

At present, the Class G airspace up to 700 or 1200 feet ( above ground level ) is pretty much do-as-you-please in the USA outside restricted or prohibited areas. You can fly unmanned balloons, helicopters, Macross robots... whatever. Essentially the FAA has no jurisdiction below 700 feet ourside controlled zones, so if you avoid those you can basically fly anywhere you want.