Hey Daniel,
People play regularly at the weekends. There is a Saturday Night Flight thread with details about the Saturday game. I believe that is the most popular night for gaming (although I only have evidence from my own experience to support this).
Only having the demo will be an issue however. You can't have more than three people playing in the demo version (Helm, Tactical and Captain), and few people who play still have the demo installed. Also, with the demo version you cannot join games hosted using the full version.