Providing network services access anytime and anywhere is nowadays a critical issue, especially in disaster emergency situations. A natural response to such a need is the use of autonomous flying drones to help finding survivors and provide network connectivity to the rescue teams. We propose VESPA, a distributed algorithm using only one-hop information of the drones, to discover targets with unknown location and auto-organize themselves to ensure connectivity between them and the sink in a multi-hop aerial wireless network. We prove that connectivity, termination and coverage are preserved during all stages of our algorithm, and we evaluate the algorithm performances through simulations. Comparison with a prior work shows the efficiency of VESPA both in terms of discovered targets and number of used drones.