Jara, no go. Just tried the static planes only option and this is the message I'm getting. I thought I have all the correct mods installed? Here's the list of the mods.
Mea culpa, Fullofit.
You are right, there was a bug in the code.
Fixed version, WOFF UE Mission Editor 1.5.6 is available
here Revision changes:
1) Fixed bug in Populate Airfields method causing false warning "Realistically populated airfields mod not installed", thx to Fullofit for pointing it out
My apology.