Is there any way to make a check zone trigger on proximity to a plane ...

[PatrickAWlson]

... instead of a fixed position?  

 

SetObject makes it trigger when the designated plane comes close to the CZ position.

Coalition makes it trigger when any plane comes close to the CZ position.

 

What I was looking for was a way to make a CZ trigger when a coalition comes close to a plane.

[Sketch]

Why not use a Proximity MCU? (or am I misunderstanding your request?)

[Gambit21]

Yep - proximity.

DCS has moving trigger zones that you assign to a unit - but essentially the same functionality.