Yeah, they call us weird, but we know the good stuff
Sorry, I misremembered, the code should actually scale all air units, but it seems that it worked only on some units and only partially for me. I suspect that you may have to clear the cache first (which I do not want to do right now as I am in the middle of a game):
Code:
UPDATE ArtDefine_UnitMemberCombats SET MoveRate = 0.5*MoveRate;
UPDATE ArtDefine_UnitMemberCombats SET TurnRateMin = 0.5*TurnRateMin WHERE MoveRate > 0;
UPDATE ArtDefine_UnitMemberCombats SET TurnRateMax = 0.5*TurnRateMax WHERE MoveRate > 0;
VP currently doubles (or tripples???) the air units move rate, so the above code should halve it back to where it was. You can try lowering the numbers even more. Now, where to add the code: Either into a file which is loaded after VP makes the changes (I ran a quick search and did not find the file), but I think Balance Changes/Units/AirUnits.sql might work. But the safest and permanent solution (even after you update VP to a newer version) would be this mod-mod which is loaded after VP:
https://forums.civfanatics.com/threads/change-vp-options.620079/
Just add the code into its Code.sql
Edit:
I actually checked the speed numbers in a mod adding a new air unit (B-52), and maybe this code will work better:
Code:
UPDATE ArtDefine_UnitMemberCombats SET MoveRate = 2;
UPDATE ArtDefine_UnitMemberCombats SET TurnRateMin = 0.15 WHERE MoveRate > 0;
UPDATE ArtDefine_UnitMemberCombats SET TurnRateMax = 0.35 WHERE MoveRate > 0;
These are numbers for a "formation" of a single big B-52 bomber, so I am not sure how the turn rates will turn out for the formations of multiple small fighters, you have to try it out.
I'd try out the above code myself, but if I launch Civ now, I won't get my children to bed, so you are on your own for now

Maybe I will try it after they fall asleep - if I wake up.