(Photo by Lars Plougmann via Shanghaiist)
Presently, getting between Pudong and Hongqiao is a time-consuming undertaking regardless of whether you take a taxi, bus, or train.
However, that will soon change (well, in several years) when the city opens a direct airport-to-airport rail corridor. Shanghai is currently in the process of planning a high-speed express railway line that would connect the two airports, with journeys taking under 40 minutes. (Shanghaiist)