Most likely, the most coveted gadget in Back to the Future II was Marty’s (pink) hoverboard. This is probably why in 2014 the so called HUVr Tech company played a major prank on gullible consumers and, under the motto “The Future has Arrived”, released a commercial where Tony Hawk himself, as well as other celebrities, explained how well their new hoverboard actually worked. The disappointment among eager consumers was so huge that Hawk and the others had to apologize to the public later for their participation in the “joke”.
This is also probably why Hendo Hoverboards talked Hawk into trying their own hoverboard when they went to Kickstarter for funds.
After the HUVr Tech fiasco, their proposal was probably received with skepticism and it was less than likely that someone would back the 10000 USD to purchase one of their first platforms. However, their Hawk video actually looks more realistic: the hover is almost touching the floor and its not that stable, either.
It’s not like they are going to explain how they do it, but taking into account the platform motion and how the floor looks, the secret beneath might be Lenz’s Law. One might have actually watched a popular science-fair trick: drop a magnet inside a copper tube and its fall will slow down considerably or even stop.
Lenz’s law states that an induced electromotive force always gives rise to a current whose magnetic field opposes the original change in magnetic flux. The idea is basically that when the magnet falls into the conductor, it generates a current and, hence, a magnetic field, that is bound to oppose the fall of the magnet.
The only requirement for this effect is that the conductor must be non-magnetic, that is every metal except iron and steel. The best choice to obtain a strong current would be silver, but for obvious reasons one has to do with copper or aluminium (in this order).
Hard core physicians may find a more detailed explanation on how Lenz’s law works on a plane in here. Unfortunately, a magnet falling slowly through a pipe is not evidence enough than a board will be able to keep your average person on air, right? The trick might be to arrange magnetic fields properly and feed them enough power. And to have a metallic non magnetic floor, too.
Even if they manage to develop this as a product, there are strong limitations to its use, plus its mobility seems to be severely restricted. However, if you have 10000 USD to spare and want to give it a go, here’s their kickstarter. You are on your own, though!