  Wireless access points on unmanned aerial vehicles (UAVs) are being
considered for mobile service provisioning in commercial networks. To be able
to efficiently use these devices in cellular networks it is necessary to first
have a qualitative and quantitative understanding of how their design
parameters reflect on the service quality experienced by the end user. In this
paper we set up a scenario where a network of UAVs operating at a certain
height above ground provide wireless service within coverage areas shaped by
their directional antennas. We provide an analytical expression for the
coverage probability experienced by a typical user as a function of the UAV
parameters.
