In this research paper the implications of Unmanned Aerial Vehicles (UAV) being refuelled in flight by another UAV is addressed for specific requirements relating to aerodynamics and flight stability. Low speed flight, less than 150KTS, introduces unique flight and stability problems that can be exacerbated by weather conditions. The methods suitable for refuelling have been researched and presented in previous papers by the authors and drogue systems are justified as being operationally feasible with significant aerodynamic characteristics. Nevertheless, these drogue systems do have flight stability problems needing addressed. Not least of these stability problems is docking when weather conditions are less than optimal. In this research the data for Wind tunnels and Computational Fluid Dynamics are used in an Experimental Design system based on a full factorial orthogonal array. The data generates statistical values offering designers and users of UAV that require refuelling a unique insight for allowing operational usage in weather conditions previously problematic. This increase operational possibility extents not only the range but regions where weather might influence deployment of UA