Now when Chongqing flies to Shanghai, it all lands at Pudong Airport. Full fare 1490, plus airport construction fee in 50 yuan and fuel surcharge in 40 yuan. The total discount is 1580. There is not much discount recently, and it will be low in the off-season. You'd better call the local ticket office. All airlines will introduce good sales policies. You can ask the conductor to design the lowest price route for you.