ZK has this really great widget by default enabled, which when you press CTRL and use area attack then units will be divided between targets.
As for air play, do you often use it and if you use the basic area attack then why?
I personally find basic area attack very useless for air because for almost every aircraft, be it Swift or Raptor or any bomber, it make a very unoptimal attack. So I would prefer the default area attack to have the spread behavior, but looking at code I realize it's not trivial to implement to cover all posible cases.