WASHINGTON, D.C.With a high-pitched screech, a hoverboard lifts a rider one inch off the ground, floating on a cushion of air across a copper-plated stage.

The scene wasn’t as swashbuckling as Marty McFly’s spin on a floating skateboard in the 1989 movie “Back to the Future II.” But Marty’s ride—depicted as occurring in October 2015—was Hollywood fiction.

This one showcased real technology. The Hendo hoverboard, which uses a new kind of magnetic levitation, or maglev, appeared at Smithsonian magazine’s “Future is Here 2015” festival that ended April 17 in the nation’s capital, along with IBM's Watson and Lockheed Martin’s Exoskeleton.

Hendo is certainly not the first thing to hover. Helicopters have long done so. Bullet trains also hover, allowing them to go super