  The integration of small-scale Unmanned Aerial Vehicles (UAVs) into
Intelligent Transportation Systems (ITSs) will empower novel smart-city
applications and services. After the unforeseen outbreak of the COVID-19
pandemic, the public demand for delivery services has multiplied. Mobile
robotic systems inherently offer the potential for minimizing the amount of
direct human-to-human interactions with the parcel delivery process. The
proposed system-of-systems consists of various complex aspects such as
assigning and distributing delivery jobs, establishing and maintaining reliable
communication links between the vehicles, as well as path planning and mobility
control. In this paper, we apply a system-level perspective for identifying key
challenges and promising solution approaches for modeling, analysis, and
optimization of UAV-aided parcel delivery. We present a system-of-systems model
for UAV-assisted parcel delivery to cope with higher capacity requirements
induced by the COVID-19. To demonstrate the benefits of hybrid vehicular
delivery, we present a case study focusing on the prioritization of
time-critical deliveries such as medical goods. The results further confirm
that the capacity of traditional delivery fleets can be upgraded with drone
usage. Furthermore, we observe that the delay incurred by prioritizing
time-critical deliveries can be compensated with drone deployment. Finally,
centralized and decentralized communication approaches for data transmission
inside hybrid delivery fleets are compared.
