1. Flights can only originate from focus cities, and planes can only fly from cities that they can touch. To get a B-C/D flight you would have to create B as a hub. However, A-C is a valid route (if it can fly the distance). Small variances may occur due to the alliance feature (which allows limited use of your allies focus cities, shared alliance wide. This can be nice and useful, or can be detrimental to your own airline depending on who is in the alliance. Alliances unfortunately aren't as flushed out as i'd like, but I'm working on a slightly more important thing at the moment.
2. .5 frequency is our way of saying it is a one-way flight. in other words, today it flies A-B, tommorrow it flies B-A, and repeats.
3. That's fine, the date is the same for everyone. We'll be having a reset at Dec. 31 2007 to start a new age. The game will likely go down for a day or two as me and stephen have a few things we need to tweak between ages however i will try to keep this time as small as possible. At this point, everyone will start fresh and on the same playing field, so take the time in this age to really try some stuff out.
4. Focus cities can be created, you must meet a few small conditions. First. the new desired hub MUST be on the same continent you started on, we operate a continental open skies theory here. (Keep in mind, Central America and the Middle East are treated in game as separate continents, which may throw you off at first). Second. You need 4 rented gates minimum at the desired airport to establish a focus city, after this point as long as you have a gate there you can maintain the focus city. Third, you need enough cash.
5. A day = game month = 1 game month is 24 days; typically the month change occurs at the same time everyday however necessity may make me or stephen advance the game by a day to ensure a modification to the hourly script is working properly (this is relatively infrequent).
Hope that helps, feel free to ask some more. I'm hoping stephen can get the wiki up again shortly, it didn't like the simpleness of my attempt to move it so now it's picked a fight with him (as i'm busily working on something else).