Is a "landline" actually a traditional land line?

You'd have to check with the provider. AT&T doesn't have a wire line service in Connecticut. 

Landline is the traditional copper feed POTS. The other is digital phone service. Though most use the term landline for both. 

POTS is only delivered via copper. Digital phone service can be delivered by fiber or copper. Whether POTS or Digital, service comes from a central office.

I guess my real question is: If I add a new "landline" now, would it be a traditional POTS copper feed or would it be VOIP?

In Branford CT. 

Thanks.

In 2014, AT&T sold their Connecticut assets to Frontier Communications so you'd have to ask them.