Based on the rapid growth in the applications of Unmanned
Aerial Vehicles (UAVs) in the last decade, the idea of in-flight communication
among UAVs has been proposed in cooperative missions. Since medium and small
sized UAVs are cheap and deployable, several of them can be used to form what
we call an Unmanned Aeronautical Ad-hoc Networks (UAANETs). Due to the
availability of location information, geographic protocols can be an option for
routing in UAANETs. Although we show that greedy geographic forwarding alone is
not sufficient in UAANETs, our results illustrate that a combination of greedy
geographic forwarding with a reactive mechanism, which forms a
Reactive-Greedy-Reactive (RGR) routing, can be beneficial. Simulation results
show that RGR outperforms existing protocols such as Ad-hoc On-demand Distance
Vector (AODV), and greedy geographic forwarding in searching missions in terms
of delay and packet delivery ratio while its overhead is comparable with
traditional mechanisms.