Elon Musk has made a statement that might not surprise many, given his reputation. The eccentric billionaire says he’s “dying” to expand beyond cars and trucks with Tesla and make an electric supersonic jet.

The planes would leverage vertical take-off and landing (VTOL) technology to reach high altitudes, before using battery-powered propulsion to achieve speeds in excess of 1,236km/h. Musk said the only thing holding him back from creating the next-gen aircraft is his current workload.

Two propulsion systems to power the jet

“I’m so dying to do a supersonic, electric VOTL [sic] jet, but adding more work will make my brain explode,” he tweeted. It’s not the first time he has voiced his ambitions to develop an electric jet, having proposed a detailed concept during a podcast.

“I have a design for a plane,” he said. “The exciting thing to do would be some kind of electric vertical takeoff and landing, supersonic jet.” The concept would feature two propulsion systems: one to lift the aircraft, while the other will propel it forward at supersonic speeds.

“The interesting thing about an electric plane is that you want to go as high as possible but you need a certain energy density in the battery pack because you have to overcome gravitational potential energy,” he said.

Musk working on eco-friendly travel options

“Once you’ve overcome gravitational potential energy and you’re at a high altitude, the energy you use in cruise is very low, and then you can recapture a large part of your gravitational potential energy on the way down. The higher you go, the faster you will go for the same amount of energy. And at a certain altitude you can go supersonic with less energy-per-mile – quite a lot less energy per mile – than aircraft at 35,000 feet.”

Musk also has another form of transport called the Hyperloop. It is supposed to be a vacuum tube pod that will move at extremely high speed from one point to another. He has backed his competition to encourage its development. He hopes that Hyperloop networks will offer an eco-friendly option for air travel.