I think that the naval war might make a good expansion for WOFF.
Brandenburg seaplanes raiding British towns. RNAS raids on Zeebrugge
Reconnaissance missions looking at shipping in the channel ports or U-boat raiders.
Of course, the RNAS mainly used airships for anti submarine patrol.
There was a Felixtowe flying boat in previous versions of the game.
I have had ideas for a mod in this direction (channel ports with shipping) but my modding skills are still in their infancy so this is some way off yet.