A car that runs off plants and sun. Another that’s powered by solar panels. How about an electric fuel-cell scooter—that can fly!

These are some of the future modes of transportation dreamed up by kids imagining a world of more fuel-efficient vehicles. Here at Consumer Reports, that’s also a world we like to dream about and feel is important for drivers and the automotive industry.

In our video above, we talked some of these young dreamers who entered their fuel-efficient car ideas in the Create Tomorrowland XPrize Challenge, a contest run in partnership with Disney and XPrize, a nonprofit known for its boundary-pushing competitions for adult scientists. 

Consumer Reports' Director of Auto Testing Jake Fisher and MIT Mechanical Engineering Professor Amos Winter teamed up to playfully weigh in on four of the concepts on video.

Photosynthetic-Fueled Car by Katrina, 14 years old

Photosynthetic-Fueled Car by Katrina, part of Disney's Create Tomorrowland XPrize Challenge

Katrina’s idea harnessing the power of the sun and plants to create fuel for the cars of the future is an idea already in the works. Primarily being tested on military and commercial trucks in the form of diesel/algae blends, algae fuel is nearly a carbon-neutral fuel source because it removes carbon dioxide from the atmosphere. Hopefully a commercially viable process of producing algae-based fuel will be readily available by the time Katrina learns to drive. 

Air Compression Car by Jaden, 14 years old

XPrize contest Air Compression Car by Jaden

Jaden’s progressive idea is for a car’s roof to harness the sun with solar panels that power a turbine motor. So far, car-mounted solar panels have solely been used on production cars for low-wattage features, such as infotainment systems, because the size of solar panels needed to capture enough energy to recharge a car are still too big. Futuristic (and failed) car company, Aptera, a former XPrize competitor, had plans for solar assistance on its high-efficiency three-wheel car. Other automakers, including Fisker, Ford, Mazda, and Toyota have also toyed with solar assistance.  

Flying Car by Lila, 11 years old

XPrize contest Flying Car by Lila

The flying car has been a fantasy form of transportation since long before the Jetson’s aerocar. One company, Moller International, has for years been planning a gas-powered, spaceship-looking recreational vehicle that will be a combination boat, hovercraft, ATV, and snowmobile, but hasn’t been able to get off the ground. Massachusetts-based Terrafugia believes that the future of personal air transportation is near. That company is developing the Terrafugia TF-X, a semi-autonomous four-seat hybrid electric flying car. While still under development, Terrafugia is taking reservations for buyers, Lila! 

Electric Fuel-Cell Scooter by Jason, 13 years old

XPrize contest Flying Car by Lila

Hydrogen-powered electric fuel-cell vehicles have been on the roads for about a decade now, albeit in very small numbers. Companies as diverse as General Motors, Honda, Hyundai, Mercedes-Benz, and Toyota have been offering special leases on such cars. Fuel-cell vehicles are electric vehicles that produce their power onboard through a chemical reaction between the hydrogen and oxygen. Hydrogen is a plentiful resource, but its storage and transportation solutions remain a challenge. Jason’s idea of using water to create hydrogen through electrolysis to power an engine is a forward-looking way of creating renewable energy. We’re not so sure about the flying part, though.