  In this paper, we propose the integration of tethered flying platforms in
cooperative vehicular ad hoc networks (VANETs) to alleviate the problems of
rapid urbanization. In this context, we study the performance of VANETs by
deriving approximate outage probability and average achievable rate expressions
using tools from stochastic geometry. We compare between the usage of networked
tethered flying platforms (NTFPs) and traditional roadside units (RSUs). On the
other hand, the rapid increase of smart devices in vehicles and the upcoming
urban air mobility (UAM) vision will congest the spectrum and require increased
data rates. Hence, we use non-orthogonal multiple access (NOMA) to improve
spectral efficiency and compare its performance to orthogonal access schemes.
Furthermore, we utilize millimeter-wave (mmWave) frequencies for high data
rates and implement a sectored beamforming model. We extensively study the
system using three transmission schemes: direct, relay, and hybrid
transmission. The results show that when acting as relays, NTFPs outperform
RSUs for larger distances between the transmitting and the receiving vehicles,
while RSUs outperform NTFPs for short distances. However, NTFPs are the best
solution when acting as a source. Moreover, we find that, in most cases, direct
transmission is preferred to achieve a high rate compared to other schemes.
Finally, the results are summarized in two tables that provide insights into
connecting VANETs by selecting the most suitable platform and type of
communication for a given set of parameters, configurations, and requirements.
