In this paper, we consider a new UAV-aided intelligent wireless sensing scheme where the UAVs are deployed for smart sensing and collecting data from Internet-of-Things (IoT) devices. In particular, we propose optimal UAVs' path planing approaches for minimising the completion time and total energy consumption of the UAVs' deployment for data collection. Two optimal schemes namely optimal energy consumption by peer-to-peer UAV-IoT sensing networks and optimal energy consumption by clustering UAV-IoT sensing networks, are considered. The low-complexity procedures of our advanced optimisation techniques are suitably applied to disaster relief networks when the solving time must be strictly adhered to. Our real-time optimsation algorithms result in low computational complexity with fast deployment and low solving time for the problem of tracking and gathering sensor data, i.e., in very short time (milliseconds). Through simulations results we demonstrate that our proposed approaches for UAV-aided intelligent wireless sensing for the IoT are suitable for time-critical mission applications such as emergency communications, public safety, and disaster relief networks.