I believe ROF ICE has an offline version now where you don't have to be connected to the net to play. One mo, I read about it in a simHQ re-review...
http://www.simhq.com/_air13/air_444d.html
This is for standard ROF...I'd be very surprised if they've changed it back for ICE.
I must admit...it's tempting me too...although I think I'll need to upgrade a few components first...but it looks and sounds just beautiful, and they've now got the Sopwith Pup as flyable, so that swings it a lot in favour for me.