  Traffic Management in Advanced Aerial Mobility (AAM) inherits many elements
of conventional Air Traffic Management (ATM), but brings new complexities and
challenges of its own. One of its ways of guaranteeing separation is the use of
airborne, stand-alone Detect-And-Avoid, an operational concept where each
aircraft decides its avoidance maneuvers independently, observing right-of-way
rules and, in specific implementations, some form of pairwise coordination.
This is a fundamental safety element for autonomous aircraft but, according to
our research, is not sufficient for high-density airspaces as envisioned for
urban environments. In these environments, some way of explicit and strategic
traffic coordination must be in place, as done for conventional ATM. For
efficiency reasons, ATM is evolving to more flexible uses of the airspace, such
that the use of dynamically allocated corridors is a rising concept for AAM.
These strategic forms of traffic coordination are potentially highly efficient
if the aircraft adhere to their trajectory contracts and there are no
significant perturbations to the traffic. However, if significant perturbations
occur, such as loss of data communication, or the sudden appearance of an
intruder, a centralized system may not react appropriately in due time. In busy
scenarios, even small deviations from plans may compound so rapidly as to
result in large differences in the overall achieved scenario, resulting in
congestions and convoluted conflicts. Therefore, it is worth studying traffic
coordination techniques that work locally with shorter look-ahead times. To
that end, we explore an airborne collaborative method for traffic coordination,
which is capable of safely solving conflicts with multiple aircraft, stressing
its capabilities throughout a large number of scenarios and comparing its
performance with established methods.
