I fly with friends over a Local Area Network.
Here are some questions about multiplayer:
1. Can ATC be used during multiplayer?
2. Does everyone have to have the exact same plane for   you to see it as the plane they selected?
(If player A chooses an F-15, do I have to have the same F-15 on my computer in order to see his aircraft as an F-15?)
3. Why are there no AI aircraft in multiplyer?

Are there any tricks or plugins to fix these?

3. My theory why there isn't any AI traffic in MP is that if you only have stock AI, your traffic.bgl file is what, not even 10 mb? I'm using PAI AI airline packages and my traffic.bgl file is about 30 mb, and I'm not even using all their files

If You and I flew MP with each other, there would be no way for my FS2002 to send all the AI routes plus tje aircraft models used to you, Even if it did add them as seperate 'players', it would bog the game down too much for the both of us