If you go with a proxy visa service, a service that gets the visa for you for a fee, it's not necessary to have the flight info. I went to China last year and in '06 and both times, didn't get the ticket until after the Visa was granted. However, you need to provide specific dates of travel. I'd check with any proxy service you are using prior to betting on this, as the situation may have changed.
If you are looking to travel into any special administrative region of China, such as Tibet, you need an additional visa for that area and for that you MUST provide flight info.