Actually, I've just solved my problem...
One has to keep in mind that the FC3 planes are available both as a bundle and individual planes.
What was failing, were the individual planes not the bundle. After uninstalling the individual planes, I realised that I still had proper access to the FC3 planes from the FC3 menu item in the mission, instant action, etc.
Perhaps, you are in the same situation !?
Cheers !