AC's rule is "All scheduled VARIG/ Nordeste/ Rio-Sul flights on qualifying paid fares. Not eligible: charter flights and code-share flights operated by any VARIG code-share partner other than Star Alliance Airlines".

Star Alliance Website says: "If you are a member of any Star Alliance™ carrier's frequent flyer programme, you'll earn qualifying miles* when you fly any of the member airlines. You can also redeem your miles for reward travel on any Star Alliance airline. What's more, you can apply mileage points from qualified flights on any Star Alliance airline toward your overall frequent flyer status."

United is explicit in "*Flights between Rio de Janeiro and São Paulo are not eligible for flight credit".

Sounds like not so seamless an alliance.