Key Differences Between eVTOL and EV Motors: Cost, Weight, and Safety Explained

Electric vehicles—whether on roads or in the skies—share a common foundation: electric motors. Yet the engineering priorities for electric vertical take-off and landing (eVTOL) aircraft diverge significantly from those of ground-based electric vehicles (EVs). Key differences include component costs, weight optimization, and safety redundancies.

Jon Wagner, who spent five years as senior director of battery engineering at Tesla, transitioned to Joby Aviation in 2017. As the leader of power train and electronics at Joby, he recently discussed these distinctions with IEEE Spectrum.

How eVTOL Motors Differ from EV Motors

Cost vs. Weight Trade-offs

Wagner explains that ground transportation prioritizes cost efficiency over weight reduction. Manufacturers weigh whether spending more on components to save weight is justified. In aviation, however, the trade-offs extend further. eVTOL developers often accept higher costs to achieve lighter weight or greater efficiency.

Safety and Redundancy Requirements

While both sectors use similar motor technologies, aviation demands stricter safety measures. Ground vehicles can mitigate failures by pulling over, but aircraft require redundancy to ensure continued safe flight and landing. This drives design choices that prioritize fail-safe systems over cost.

Is Redundancy Built into EV Motors?

Wagner notes that redundancy is rarely the primary goal in EV motor design. Some all-wheel-drive vehicles feature front and rear motors, which incidentally provide redundancy. However, this is a secondary benefit, not the main objective.

Joby Aviation’s Manufacturing Approach vs. Traditional EV Production

Wagner highlights a key advantage of Joby’s eVTOL development: highly integrated solutions. In mature industries like automotive, efficiency often comes from outsourcing components to specialized suppliers. While this reduces costs, it introduces inefficiencies at system interfaces. Joby’s approach avoids these penalties by designing integrated systems from the ground up.

Cutting-Edge Materials in eVTOL Motors

Wagner expresses excitement about Permendur, a cobalt-iron alloy. Though Permendur costs approximately 10 times more than traditional motor steel, its performance improvements make it viable for aviation. Ground transportation typically avoids such materials due to cost constraints.

Will Electric Aircraft Match EV Adoption?

While Wagner remains optimistic about electric aircraft’s future, he acknowledges the challenges ahead. His forward-thinking perspective on power-train innovation underscores the potential—and the hurdles—of eVTOL adoption.