Originally Posted by
sinoflyer
The rules above do not stipulate what constitutes a stay, a stopover, or how to determine the ultimate destination. As long as the onward ticket is for a third country, the traveler qualifies for TWOV.
OP is right; AA is wrong.
Here's a legal opinion regarding TWOV 3rd country.
Gary Chodorow (乔德睿) is a China-based immigration lawyer. He has helped clients with U.S. and China visas, permanent residence, and citizenship matters for more than 20 years. Gary also is a founding member of the American Immigration Lawyers Association’s Asia-Pacific chapter, co-chair of the American Chamber of Commerce-China’s visa committee, and adjunct professor at Chicago-Kent School of Law.
Note that the third country or region must not be the originating country. For example, New York -> Beijing -> New York does not qualify, but New York -> Beijing -> Tokyo -> New York does qualify.
Duration of stop in third country is irrelevant (e.g., LAX ->PVG -> NRT -> LAX is OK, even if NRT stop is for only a few hours).
http://lawandborder.com/china-72-hou...t-visa-waiver/