Specialized ad hoc networks of unmanned aerial vehicles (UAVs) have been playing increasingly important roles in applications for homeland defense and security. Common resource virtualization techniques are mainly designed for stable networks; they fall short in providing optimal performance in more dynamic networks such as mobile ad hoc networks (MANETs)-due to their highly dynamic and unstable nature. We propose application of Opportunistic Resource Utilization Networks (Oppnets), a novel type of MANETs, for UAV ad hoc networking. Oppnets provide middleware to facilitate building flexible and adaptive distributed systems that provide all kinds of resources or services to the requesting application via a helper mechanism. We simulated a homeland defense use case for Oppnets that involves detecting a suspicious watercraft. Our simulation compares performance of an Oppnet with a baseline case in which no Oppnet is used. The simulation results show that Oppnets are a promising framework for high-performance ad hoc UAV networking. They provide excellent performance even under imperfect (and realistic) conditions, such as a less invasive use of helpers, denial of help by some of the candidate helpers, and imperfect detection capabilities of Oppnet components. (C) 2013 Elsevier Ltd. All rights reserved.