you have to edit aircraft.cfg file (wiki how to: SimFly Client – SimFly ) g´luck
i.e (inserting icao “C208” such as did (and don´t forget BS C208 has 2 aircraft´s , one with cargopod and other “plain” - without cargopod)
inside file, search and insert icao (C208) after “ but in front of all sentence. lines Title and ui_variation
[FLTSIM.X]
Title=“C208 Black Square Caravan Professional Gear N95EJ”
…
ui_variation=“C208 N95EJ”
for me, worked