My Airfix Hunter,the very first kit I built,nearly 60 years ago,was in black plastic.
Ah yes, I remember that! It came in a poly bag and had either RAF or Swiss transfers. But before that came out (which must have been around 1960?), there was rather a poor Frog model which came in silver grey plastic. My late father made one for my brother, but our Hunter-flying family friend 'Farmer' Steele said it wasn't very accurate as it didn't have the saw tooth leading edge. As an A1 QFI, he could explain aerodynamics in terms which I understood as an 8 year old!