Gday @Z_123 , As far as i know, "Airplane Mode" should disable both, wifi & bluetooth.
There maybe several reason's for this behavior,
Eg: Bios settings
systems update/upgrade... etc..
Please let us know, how you are running ZorinOS, ( clean, dual boot, usb, etc)
Also what is the pc?
This link may trigger a clue aswell,
Try that second link in the post above " Make airplane sane again".
You may also search for that, in relation to Ubuntu OS,,, as ZorinOS runs off Ubuntu setup.
ok, you my also need a few updates/upgrades/etc.
So first run this in "Terminal"
sudo apt-get update
Then run this,
sudo apt-get upgrade
Reboot
After about 5min's,repeat again to see if you have more updates?
Next run,
sudo ubuntu-drivers autoinstall Reboot
Ok try this, ( it maybe just Knowledge )
first:
Enable both wifi & bluetooth,
Now turn on Airplane mode ( should disable both)
While in Airplane mode, you can enable wifi, not bluetooth. ( Don't ask me why hahahahaha)
If you disable wifi, while in Airplane mode, It will remain disabled , when you turn off Airplane mode.
Old "Airplane Mode" automatically turn both off.
New "Airplane Mode" you can "Enable" wifi at the same time.