Role of flying cars in sustainable mobility

Abstract

Interest and investment in electric vertical takeoff and landing aircraft (VTOLs), commonly known as flying cars, have grown significantly. However, their sustainability implications are unclear. We report a physics-based analysis of primary energy and greenhouse gas (GHG) emissions of VTOLs vs. ground-based cars. Tilt-rotor/duct/wing VTOLs are efficient when cruising but consume substantial energy for takeoff and climb; hence, their burdens depend critically on trip distance. For our base case, traveling 100 km (point-to-point) with one pilot in a VTOL results in well-to-wing/wheel GHG emissions that are 35% lower but 28% higher than a one-occupant internal combustion engine vehicle (ICEV) and battery electric vehicle (BEV), respectively. Comparing fully loaded VTOLs (three passengers) with ground-based cars with an average occupancy of 1.54, VTOL GHG emissions per passenger-kilometer are 52% lower than ICEVs and 6% lower than BEVs. VTOLs offer fast, predictable transportation and could have a niche role in sustainable mobility.

Robust Environmental Life Cycle Assessment of Electric VTOL Concepts for Urban Air Mobility

“…We consider the limitation of our LCA to global warming reasonable, as it is one of the most pressing sustainability issues to date [17]. Also, this approach is in line with the referenced study by Kasliwal et al [9].…”

“…A study recently published in 'nature Communications' by Kasliwal et al demonstrates that eVTOL may, in a constrained scenario, be able to environmentally compete with internal combustion engine vehicles, and possibly with battery electric vehicles [9]. The authors demonstrate the criticality of trip distance for the overall carbon efficiency and show that eVTOL can, in certain cases, beat ground-based cars in terms of emissions per passenger transported.…”

Scenario-Based Strategic Planning for Future Civil Vertical Take-off and Landing (VTOL) Transport

“…Without effective resolutions such as new or reconfigured runways, congestion at major airports is expected to cause more and more delays in travel time and unnecessary costs for both airlines and passengers. In this context, in the last decade, technical advancement with the potential civil VTOL transport has gained significant interest both in research and investment due to the multiple socio-economic factors, such as massive fuel costs, noise reduction, and user benefits in the air transportation industry (Kasliwal et al, 2019).…”

“…• Goal 4: Competitive operation and maintenance costs. VTOL is efficient when it cruises but consumes substantial energy for takeoff and climb (Kasliwal et al, 2019). Also, because lift engines serve as deadweight while cruising, more weight and distance it needs to transport, which means more fuel needs to be consumed.…”

The Prospects of on-demand Urban Air Mobility in Zurich, Switzerland

“…The concept promises to remove some traffic from the roads and to move it to the uncongested skies, thus reducing some of the negative effects of the car. While the positives of the concept are yet subject to research (some results can be found in [7], suggesting that under some circumstances VTOLs can be more energy efficient than ground vehicles), it is interesting to evaluate what may be the actual market penetration of such a service around the world. In the near future, as the technology is yet to mature, it is expected that the service will be costly and only accessible to the few, as was the case for both automobile and long-distance aircraft travel.…”