Urban air mobility (UAM) is a proposed multimodal transportation system in which aircraft, often envisioned as electric vertical takeoff and landing (eVTOL) aircraft, fly between designated aerodromes within a metropolitan area, and ground-based transportation provides first- and last-mile connectivity to and from those aerodromes. If introducing UAM operations results in a substantial increase in trip-related carbon dioxide ([Formula: see text]) emissions, this could present a limit to the broad adoption of this mode of transport. This study estimates the mode choice and associated [Formula: see text] emissions of daily trips across the Chicago, IL, and Dallas, TX, metropolitan areas in several scenarios. Travelers select a mode of either a personally owned ground vehicle or UAM based on an effective cost metric. The analyzed scenarios include the impact of ridesharing in eVTOL aircraft along with various levels of electrical grid [Formula: see text] emissions intensity and electric ground vehicle (EV) adoption rates. Results indicate that ridesharing-enabled UAM operations can lead to reduced [Formula: see text] emissions compared to scenarios without UAM when EV adoption rates are less than 80%. Based on this, [Formula: see text] emissions do not appear likely to pose a significant limit on UAM operations with ridesharing.

Wildfires are increasing in frequency, intensity, and duration, driving up suppression and damage costs and motivating a more coordinated use of aerial firefighting assets. Within this context, we extend the COLOSSUS Project’s X-Challenge System-of-Systems (SoS) simulation toolkit with an integrated aircraft sizing and fleet assessment methodology that links conceptual aircraft design with tactic selection. Two platforms are sized under 2035 technology assumptions—a 2000 kg payload electric Vertical Takeoff Landing (eVTOL) and a 3000 kg payload Single Engine Air Tanker (SEAT) using physics-based performance and parametric cost models. A Design of Experiments (DoE) workflow coupled with the SoS toolkit evaluates mixed fleets and tactic assignments in three representative regions. Effectiveness is quantified via a weighted, normalized Measure of Effectiveness that aggregates burnt area, emissions, and cost metrics into a single scalar. Results show that acquisition cost dominates overall effectiveness and that location-specific fleet compositions can outperform a single fixed fleet without degrading suppression outcomes, motivating future work on adaptive, region-specific fleet design and sensitivity analyses.