You can fly over a city which is congested, by following railroad tracks, etc, those areas are uncontested. But, you must be in class E or G airspace, unless you have clearance from the controlling agency.

The FAR 103.11(b) is only for flying with strobes, during civil twilight. You must be in uncontrolled airspace, which is class G, generally, but not always, starting at 700 or 1200 feet AGL.

Where I live ..0-500 feet is class G and class B starts at 500' ago. So I could fly my ultralight at 400'  , 20 minutes after sunset, along railroad tracks thru a major city.

A bad decision is called pilot error, your job is to keep others safe from your stupidity. :)

You can fly over a city which is congested, by following railroad tracks, etc, those areas are uncontested. But, you must be in class E or G airspace, unless you have clearance from the controlling agency.

The FAR 103.11(b) is only for flying with strobes, during civil twilight. You must be in uncontrolled airspace, which is class G, generally, but not always, starting at 700 or 1200 feet AGL.

Where I live ..0-500 feet is class G and class B starts at 500' ago. So I could fly my ultralight at 400', 20 minutes after sunset, along railroad tracks thru a major city.

A bad decision is called pilot error, your job is to keep others safe from your stupidity. :)