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ok, this is harsh, just as a matter of fact, it's only 20mins train ride from suzhou city center to Shanghai Hongqiao Airport...
To be fair, Suzhou did have an airport for civilian use... for only a brief moment, namely Suzhou Guangfu Airport from 1994 to 2002. Prior and afterwards, the place has been for exclusive PLAAF use.
And like you said, it's easier now to travel from Suzhou to Shanghai Hongqiao with a 20-minute train ride, which only makes the need for a Suzhou-exclusive airport redundant.