I will arrive at Shanghai International Airport at 7 PM for a connecting flight the next morning at 9. How far is the downtown from the airport? If it is not inconvenient, I would like to see the city at night and return to the airport by one or two in the morning. I have never been to the city before. Is it a bad idea? Nothing to see or do at night?

You mean Shanghai Pudong-PVG? It quite a way out of town but fhe city is so worth seeing. Walk the Bund with Pudong's buildings light display at night until 10 pm.
It is a city of more than 24 million so lots going is going on.

There is a high speed train from airport to Pudong area of downtown.

There are two airports in Shanghai. Both is international and none is called the Shanghai international airport. On one end of town, there is the Pudong airport. A bit further away but connected to the city by bus, subway, Maglev train and taxis. The other airport is called Hongqiao airport (and sometimes just "Shanghai airport"). It is a shorter ride to the center from Hongqiao.
You'll probably get to the city at about 9pm. It gives you about one hour to see the "lights" on the Bund and Nanjing road.
Check about the last transportation back to the airport.
I can't think of any place to sleep at the airport except the floor, if they let you.

Thank you for the information. Yes, it is Pudong. I guess I will have to find a hotel near the airport and do not expect to see anything in Shanghai.

Info on sleeping in or near Pudong:

www.sleepinginairports.net/asia/shanghai.htm

Official airport website:

en.shairport.com/pudongair.html

Looks like you can forget the maglev and metro, at least for the return, but the bus/night bus might work.

@HappyTrvlr - what did you mean about 10:00pm?

Thank you all. I guess i will stay at a hotel near the airport.

We were told that the "light show" on the buildings stops at 10pm where we were in Shanghai a few months ago. We didn't stay on The Bund so I can't verify it, rather stayed in the French Concession.

I would say that the Bund and the ultra-modern skyline across from it were well worth seeing with or without a light show. (Didn't have one when I was there.)

Not sure what "show" people are talking about but those bright lights and some that go on and off until 10pm have been there for more than 10 years. However it is not a "show" like in HK.