UAL last expanded to a new Chinese market with Chongqing (#5 on Trip’s list). I think they selected there because they are limited in total routes to China they are allowed to fly and they already served HKG, which is extremely close proximity to SZX. Think EWR and JFK. The cities are even connected by subways, but there is a full on customs border crossing. Once the Chinese have fully integrated Hong Kong, that will in effect be one large city.

I’ve been through SZX a lot, and it is begging for a direct US connection.