A case for carrying loads by an Unmanned Aerial Vehicle (UAV) comprises a first end comprising a first cap and a first opening and a second end comprising a second cap and a second opening, the second opening being smaller than the first opening. The case also comprises a rechargeable battery pack that, when the case is secured to the UAV, is configured to provide a power source for the UAV and the first cap and the second cap each comprising at least one metal connector for providing power to the UAV.