Question

UAV-VANETS link-up may be used for

Answer 1

node mobility, connectivity, message routing, service quality, application areas

Answer 2

UAV-VANETs link-up may be used for visual guidance, data muling and coverage enhancement. 

Unmanned aerial vehicles or UAVs form an aerial subnetwork and aid the ground vehicular ad hoc networks or VANETs in various ways. The UAVs are dispatched to areas of interest to collect information. They transmit this information to the ground vehicles. They act as intermediate relays when network partitions happen in the ground vehicular subnetwork.

So UAV-VANETs link-up can be used for disaster recovery, traffic monitoring, and military reconnaissance.