Systems and methods provide for a flexible fuel bladder assembly disposed to store fuel and supply the fuel to a vehicle. The flexible fuel bladder assembly may include: a fuel bladder including a fuel-resistant film disposed to store the fuel and supply the fuel therefrom at a manifold assembly connected thereto; and a spiral tubing disposed within the fuel bladder and disposed to prevent collapsing of any two or more sides of the fuel bladder upon each other and permit a substantial portion of the fuel to be supplied from the fuel bladder to the manifold assembly in an uninterrupted fashion until the substantial portion of fuel is removed from the fuel bladder. The flexible fuel bladder may be used in an unmanned aerial vehicle (UAV), which may be any one of: an organic air vehicle (OAV), a micro air vehicle (MAV), an unmanned ground vehicle (UGV) or an unmanned combat air vehicle (UCAV).