I looked at Anchor and Avenger, and they both say WL_Orbital, so I'm not even sure what that value means. Another example: the 58772 missile tower could also target land, but guard_layer was WL_Air. The weapons have a target_layers property that looks more promising.
The problem is that I can't find one that combines both air and land. What I am working on is a fighter that can hunt both air and ground. It is able to shoot both air and ground, however it only actively seeks one of them depending on whether its WL_LandHorizontal or WL_Air. As far as I know there are no units that currently hunt both land and air. That's why I am asking.
This has to do with the guard radius. When unit A enters within the guard radius of unit B, then unit B will move to attack unit A. However if unit A happens to be an aircraft and unit B has its guard layer set to WL_LandHorizontal, it won't react. What I want to do is have unit C react to both units D and E. However unit D is an aircraft and unit E is a land unit. With what I currently know, I can't make unit C react to both unit D and E. It can be D or E, but not both.