In high school in the mid 2000s in Denver, they had a chopper in the air on weekend nights from 8 until 2:30 am or so.

When our parties got called in, the spotlight would be the warning that the cops were a few minutes away and it was time to run.

Lots of cities have manned aircraft loitering during busy times that will respond to a call before ground units

Yes, often the first response to some calls is a CHP aircraft that continuously loiters in the area.