When Airfix released their first 1/24 kits, the theme was the BoB. If they continue with that type of logic (purely speculative concept on my part), and to complete their release of the Fw 190 and P-51, and Typhoon they could add the Me 262 , Fw 190 D, P-38 and late Spit for a late war selection. A Tempest would fit perfectly too. A D-9 exists from Trumpeter already so this type might not be considered as much but who knows...
A desert theme would be interesting too and a Macchi 202 and P-40 jump to mind!
Post war, why not the Korean war. Not so well known but nice subjects: Sea Fury, Firefly, Sabre, MiG-15, Panther.
Many of these suggestions have been made in previous posts, but I thought they could be grouped in a logical way.
Also, a EE Lightning would simply be astounding!!! One of the most iconic jets of its era!