Hello, My flight from Pudong to Bangkok departs at 6.50 am in the morning.

The earliest bus departs at about 06:00. It is a long distance and too early. It is not easy for you to hire a taxi.
Thus you can consider arriving at Shanghai pudong airport in advance a day and stay at the hotel near the airport.

Thanks for the reply. However i have searched online and i found that there are airport shuttle buses that also operate between 2300 and 0500 hrs , albeit with reduced frequency, from hongqiao train station/hongqiao airport (which are adjacent to one another if i recollect correctly).

Please check or let me know if it would be a viable option to arrive at Hongqiao train station and then take the night bus.

Thanks,
Nitin