It was a change in the WU4 of the sim.
Once you have downloaded the mod and uzipped the file, there will be two folders to choose from
If you want the version that is compatible with “OnAir Company” choose the “…_OnAir” folder. If not, choose the other one and copy it to your Community folder. Only copy one of the folders!
The layout.json file is no longer needed for the mod to work.
Therefore steps 1 and 2 of the installation process are no longer needed.
You can get the Mod here: