Do the CAS units get moved to a headless client, and if so is there a way to stop them from being moved.

All CS units have the exclusion variable set so they get skipped in the ALiVE HC script. If you're using any other HC script, CS may break.

The reason I ask is with the HC's enabled, my CAS transport pilots seem drunk , and a few times seem to land 5 feet above the ground

Could you get a server rpt up on pastebin or something, or just check the logs for ALIVE AI Distributor switching group '<group_name>' to HC '<hc_name>'..

Make sure your CS assets group(s) isn't being listed as transferred.

In my trouble shooting I could recreate the issue with RHS assets for CAS , using more than on HC.
The CAS were not being transferred to the HC's but they had guessed you would call is stuttering flight.

But using CUP assets or vanilla assets, I could not recreate the issue.

RHS also was having other issues with VCOM, like AI not using their primary weapons ,