It's the current AvA setup.
Instead of the old AvA where it was basically a dueling arena with historical planesets, in BoA there are two sides (axis and allies of course) that are organized to reach the goals of the... well, I guess you could call it a scenario, thats going on 24 hours a day.
Theres no base capture. The goal is to pound the other side's strats into nonexistence. By damaging the other sides strats and defending your own you get money. You use that money to place aircraft at airfields. There's no airframe limit, but you have to pay a historical amount to enable an aircraft at a field.
The setup basically makes it so that large scale, high altitude buff raids and other such historical missions are required, making it tons and tons of fun. It's like a 24 hour FSO. If you are interested in flying for the fatherland drop by the AvA forum and ask to be added to the Axis forum.