(svn r17719) -Change: [NoAI] Make AIEngine:CanRefitCargo() not report refittability to Mail by default for aircraft. It is not necessarily true, and the special case of carrying both passenger&mail is better handled by AIs themself than by the API.

src/ai/api/ai_engine.cpp

@@ -54,7 +54,6 @@
 	if (!AICargo::IsValidCargo(cargo_id)) return false;
 
 	if (GetCargoType(engine_id) == cargo_id) return true;
-	if (cargo_id == CT_MAIL && ::Engine::Get(engine_id)->type == VEH_AIRCRAFT) return true;
 	return ::CanRefitTo(engine_id, cargo_id);
 }