On the 18 September 2014 D. Gregory Henderson, for Arx Pax LLC, both of San Jose, California (same state as McFly, almost inevitably) had published a US patent application, Magnetic levitation of a stationary or moving object. A week later a World patent application with the same title, WO2014/149626, was published. It is 73 pages long, of which 20 pages are drawings. The final pages cite relevant prior art, and they only found "A" citations -- background, unlikely to invalidate the application. Taken from the US document, there is for example this spectacular drawing:
Here are three others.
Wired has a piece by Rhett Allain called The physics of the Hendo Hoverboard.
Arx Pax themselves seem to be a bit of a mystery. Their emblem is a dove between olive branches, and their mission statement is to be "a revolutionary technology company with the sole purpose of innovating solutions to some of the most pressing global problems of our age." I'm not sure I'd regard the problem of levitating a pressing problem, to be honest. How expensive would it be, I wonder ?
The same inventor and company had, in July 2014, a US patent granted for Methods and apparatus of building construction resisting earthquake and flood damage. The basic idea is to put buildings on a concrete structure which can float on a "buffer medium". A drawing from it is given below.
I recently wrote on the related Frankie Zapata's Hoverboard by ZR.