Hi norcalpilot
I'm not with Laminar Research, just a fellow simmer in the UK, but as long as you always have Disc 1 of the DVD set in your DVD ROM tray at all times after initial installation, you don't need to be online to get the simulator application working.
However, if you wish to download any updates at a later stage from the LR website, then you will need to be online then.
Hope this helps.
Regards