Methods, systems, and devices for wireless communication are described. A user equipment (UE), such as an unmanned aerial vehicle (UAV) (e.g., a source UAV), may initiate a unicast link establishment procedure with another UAV (e.g., a target UAV), which may enable the UAVs to communicate according to an air-to-everything (A2X) service type. The source UAV may transmit a direct communication request (DCR) message to the target UAV that includes an application-layer identifier (ID) that is unique to the target UAV. The source UAV may derive the application-layer ID for the target UAV from a UE-specific ID that is unique to the target UAV. Alternatively, the source UAV may transmit a DCR message that excludes target UAV information. Instead, the DCR message may indicate one or more proximity parameters associated with the source UAV. The UAVs may communicate unicast messages via the unicast link according to A2X configurations and communication parameters.