A US-passport carrying friend has a short (< 48 hour) layover in Shanghai en route to another country in Asia. He's getting conflicting answers re. whether he needs a visa.

The Chinese Consulate (in Chicago, I think) told him: It's up to your airline...whatever they say.
American Airlines says: No visa necessary
The US State Department says: "If Shanghai Pudong airport is your international transit point, you may stay in Shanghai for 48 hours if you have a valid passport, a visa for your destination, and an onward plane ticket. Make sure you get an endorsement stamp at the immigration desk before you leave the airport."
The visa service his company uses says: Yes, you absolutely need a visa.

I'm inclined to believe the State Department & airline, even though on FT we always tell people to get their info straight from the country in question. I find it hard to believe that the Chinese Consulate really defers to an airline's wishes, but he's a savvy traveler, so I believe him when he said that's what he was told.

Thoughts?