Jet-setters hoping to catch a ride on a Tesla-of-the-sky will have to be patient. Early investors are pouring tens of millions of dollars into electric, autonomous and vertical-takeoff-and-landing (VTOL) concepts like Zunum Aero, Volocopter and Aurora Flight Sciences. But Jim Harris, aerospace and defense partner at Bain & Company, says consumers will have to wait longer than some of those companies say. "2022 feels early to me," Harris said. "We're likely 15 to 20 years out for something like an electric aircraft used for commercial passenger transportation." Boeing, which last week acquired Aurora and is one of Zunum's main investors, represents one of many legacy aerospace companies aiming to keep up with an industry-wide push to evolve electric technology. "The legacy in aerospace is hardware with a little software. Now software is becoming a much bigger part of this," Harris said, before adding that legacy aerospace companies will have to move to a model based on software.

Three separate technologies

When it comes to electric, autonomous and VTOL, Harris believes each technology will progress independently. He says that all three "are squarely in the development phase" but, as they have separate engineering obstacles, each will "have its own timeline." Electric jets face the same battery challenges as automobiles and utilities: efficiency, risk of fires and more. "If problems with battery technology get solved, they'll get solved in automobiles and utilities," Harris said.

Artist rendering of Zunum Aero aircraft flying over Seattle Source: Zunum Aero

Aerospace is far more conservative testing new commercial products than the automotive industry, Harris noted. It will take a few years to develop even small electric aircraft, Harris says, and "the degree of testing that will be required will be very extensive." The same precautions go for autonomous, even though commercial aircraft today already have limited self-flying capabilities already. Harris defined autonomy on a gradient scale of mild-, some- and full-autonomy. He predicts airplanes with some autonomy will debut in four or 5 years, saying that "it will be more than 10 years until we see full autonomy." UBS analysts Jarrod Castle and Celine Farnaro largely agree with Harris, writing in a note on August 7 that "remotely controlled planes carrying passengers and cargo could appear by 2025." "You don't get a second chance if something happens midflight," Harris said. "Development for autonomous aircrafts involves copious testing and due diligence, which slows the speed to market, even more so than autonomous automobiles."

New infrastructure required

No matter which technology blooms first, Harris says infrastructure will need to change a lot to support autonomous . "The level of maintenance required is going to be significantly higher than on automobiles and you'll need the infrastructure to do that," Harris said.

A Volocopter 2X electric multirotor helicopter stands on display at the 2017 Frankfurt Auto Show on September 12, 2017 in Frankfurt am Main, Germany. The Frankfurt Auto Show is taking place during a turbulent period for the auto industry. Leading companies have been rocked by the self-inflicted diesel emissions scandal. Sean Gallup | Getty Images

Harris thinks general aviation facilities, currently in limited use for small, private aviation, are the first place these regional-catering technologies will look to grow. Municipal airports may also be used. Electric automobiles and alternative fuel trucks alike required serious investment to build out the infrastructure to refuel and service. Harris thinks there is an exponential benefit that comes as networks scale and more service areas emerge. "How much of existing facilities can be repurposed? An awful lot," Harris said.

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