The documentation is here:
https://springrts.com/wiki/Uikeys.txt#selectionsThe one you found is bound to Ctrl+S by default, which just selects all your Owls (apparently that's the only aircraft matching the "Radar" filter).
Incidentally, I have this handy custom one to select all "regular" army units (probably missing a few additional exclusions of units that shouldn't just move with the main army):
select AllMap+_Not_Builder_Not_Building_Not_Aircraft_Not_NameContain_Flea_Not_NameContain_Crab_Weapons+_ClearSelection_SelectAll+
I'd like to include Iris, but the language doesn't seem to have an "or".
