Alright, I'm gonna give you my 2 cents:
I feel like the event should only be about an hour long. I see this as more of a skrimish match. Anything longer and you risk teams being very uneven with players logging. There should be a sense of urgency. Many players probably wont enjoy switching teams because it is strategy based. I think evening at 10PM would work well.
The bases should be somewhat close together, maybe 12 miles at 0 alt. If planes have too long to gain alt, there could be a lot of hoarding if one team has dominant fighter cover. Long flights lead to people getting bored. Especially on the way home.
All planes should be the same for both sides. If not, this would cause an imbalance in the fight, and one team could dominate. Mid war planes, tanks would be the most fun, IMO.
Would there be other scoring other than taking the base? Would it be squad based? Either is fine, IMO. It's almost a given anyway. With score, I think it would add a certain level of deeper strategy rather than just go full leeroy jenkins every sortie for a quick reroll just to get field down.
How are objects damaged? Would you be able to take down ord, vh and fh? gotta think about that. Could make people angry when they cant roll.
Also, the other side has to realize that one team is going to have to cap and vulch if they want to take the base with only one field to roll from. This has to be mentioned because people might get mad about it and not understand.
It will be interesting to see how long it takes one side to have complete air and tank superiority to take the field, but it depends on how hard it is to take down the ord, vh, fhs, ect.
Just my thoughts for now. May have more later.