NOT TRUE!!
There is the ability for players to make custom arenas that may include them (probably). But for the first time, HTC has created missions listed that can be flown together with other online players and against AI.
Just like we have different arenas now in AH2, the beta currently has "TABS" which neatly categorizes Missions, Arenas (including the Main Arena equivalent), Events (where FSO and other sponsored events would be listed), and player created arenas (currently the Custom Tab in AH2).