Collusion Size to Flying Units

Is there any way to add collusion to air units (like it was in RoC)? I cannot find it in gameplay constants...

Isn't collision size editable in the object editor?

It is...but it doesn't work for air units even if you set it to 200...

Air units ignore collision size unless their idle. What that means is that they'll bunch up when moving but spread out when theyre not moving. You can't change that behaviour.

too bad!
but its not really needed...it would just be much better in that case...

Try setting "Movement - Group Separation - Enabled" to false.

You also might need to turn the group number, parameter, and priority to zero, although I'm not sure if its truly necessary.

This should make the unit act, basically, like a ground unit in the air with all the same collision rules.