The canonical name is flyertalk.com. www.flyertalk.com is just an alias for flyertalk.com:
The web server appears to respond to both virtual hosts with the same content.

This is incidentally not a good way to set things up. It means you can end up with two sets of cookies or site preferences or other state depending on which host name you connect to which can be confusing. It's much better to set up a virtual host for one of them that just does a 302 redirect to the preferred name and always use that preferred name.