Alliances and upgrading to business class

In the past few years I flew NW/KLM and CO/KLM. I bought
economy tickets and upgraded to business class with FF miles.
In Europe, the KLM flights were also business class. In Europe,
business class just means that you sit in the forward section of the
plane and receive better refreshments. You also are allowed heavier
luggage (30 kg versus 20 kg for checked luggage). Recently I flew
UA/Star, also buying an economy ticket and upgrading to business
class with FF miles. I was surprised to learn that my European Star
connecting flights (Lufthansa and SAS) were economy, not business.
Anyone want to comment on other airlines, like Delta and American,
with respect to their upgrade policy for partners?


Pete