If Elon Musk was not already running Tesla and SpaceX he might take up another big project: creating an electric jet. 

In fact, when asked during a recent Marketplace interview what Musk would be doing if Tesla didn't exist, he revealed that he already has a design for such an aircraft ready to go. 

“I do like the idea of an electric aircraft company. I think one could do a pretty cool supersonic, vertical, take-off and landing electric jet. That would be really fun... I have a design in mind for that," he said. 

"Then of course there is the Hyperloop, I’d probably be working on that,” he casually added. 

This is not the first time Musk has mentioned that he is interested in this kind of project. 

During another recent interview with CNN Money, Musk said that the "ideal, long distance transportation mechanism is a supersonic, vertical take-off and landing electric jet."

Musk told Marketplace that excluding rockets, he believes one day all vehicles will be electric, so he thinks it's a promising venture.

“Aircraft and ships and all other forms of transport will go fully electric. Not half electric, but fully electric. No question,” he said.

Musk, though, said he has enough on his plate right now. The visionary billionaire already runs his electric car company and SpaceX and has big plans for both companies over the next few years. 

One big goal of Musk's is getting Tesla's giant Gigafactory in Nevada into production. The company aims to make enough batteries to power 500,000 cars per year so it can finally begin production of its more affordable vehicle, the Tesla Model 3, which is expected to go into production in 2017 and be priced at $35,000. 

"We have the Model X, that we obviously have to ramp up production of. We have a complete model of the Model 3, we have the battery pack business... and so there is a lot of work that needs to be done," Musk said. "But I feel at this point Tesla is in a really solid position. And at this point it’s a matter of how quickly can we bring an affordable electric car to market — how quickly can we bring affordable battery storage to market."