I just experimented with a combination of the methods described in this closed topic.
- Create a panel folder in your custom livery folder
- Copy the original panel.cfg
- Edit the line
painting00=Registration/Registration.html?font_color=black, 0, 0, 1024, 256
found in the section [VPaintingxx] (where location = exterior) to read
painting00=Registration/Registration.html?display=none
I only tried it on the default 152, so it’s not guaranteed to work on every aircraft.
IMHO, the advantage is keeping the registry field for, well, the registry and Airline/Flight number for those, respectively. It doesn’t break ATC and accomplishes hiding the registry.
Best wishes!