I am running X-plane 11 on my Imac. Can not get the plugin to load.
Log:
Fetching plugins for /Users/claes/Desktop/X-Plane 11/Resources/plugins

Loaded: /Users/claes/Desktop/X-Plane 11/Resources/plugins/PluginAdmin/mac.xpl (xpsdk.examples.pluginadmin).

dlerror:dlopen(/Users/claes/Desktop/X-Plane 11/Resources/plugins/mac.xpl, 6): no suitable image found. Did find:
/Users/claes/Desktop/X-Plane 11/Resources/plugins/mac.xpl: mach-o, but wrong architecture
/Users/claes/Desktop/X-Plane 11/Resources/plugins/mac.xpl: mach-o, but wrong architecture
Failed: /Users/claes/Desktop/X-Plane 11/Resources/plugins/mac.xpl. (This file is missing, not a DLL or could not be loaded due to another missing DLL.)

dlerror:dlopen(/Users/claes/Desktop/X-Plane 11/Resources/plugins/HaversineAir/64/mac.xpl, 6): Symbol not found: ____chkstk_darwin
Referenced from: /Users/claes/Desktop/X-Plane 11/Resources/plugins/HaversineAir/64/mac.xpl
Expected in: flat namespace
in /Users/claes/Desktop/X-Plane 11/Resources/plugins/HaversineAir/64/mac.xpl
Loaded: /Users/claes/Desktop/X-Plane 11/Resources/plugins/Little Xpconnect/mac.xpl (ABarthel.LittleXpconnect.Connect).

I've heard about this happening with the latest plugin to users running older version of macOS (pre-Catalina). Could this be the case?

The latest plugin was compiled in Catalina due to the new signing and notarisation requirements and somehow it's missing this call to ____chkstk_darwin.
I've yet to investigate and try and produce a new plugin version that doesn't hit this, but in the meantime please download:

http://haversine.com/files/HSAIRXPL-5.4.1m.zip

It's the exact same plugin compiled on an old Mac for 64 bits which I hope does the trick.

sorry for the trouble,
joao @ haversine

Thank you - it did the trick! :-)
Brgds
/Claes