The Hoverboard concept was first introduced in the movie "Back to the Future 2". In the movie, the hoverboards were the size of skateboards and were completely noiseless with no moving parts.  But now there’s a hoverboard you can own and do your own tricks on. 

The devices shown in the movie could support the weight of a human rider and hover him several inches above the ground on a mysterious cushion of invisible magnetic energy. They could even hover over water. During a televised interview with the movies director, Robert Zemeckis, he explained that "hoverboards float on magnetic energy". He also added, "they’ve been around for years, it’s just that parent groups havn’t let toy manufacturers make them. But we got our hands on some and put them in the movie". He was only joking of course but interesting enough, Mattel(whose logo appeared on the hoverboard props) soon found themselves overwhelmed with callers asking where they could buy one. Although they looked pretty convincing in the movie, the hoverboards were simply wooden props attached to the actors feet. To make the boards fly, the actors were suspended by cables. 

This personal hoverboard uses high performance hovercraft technology to lift a 250+lb rider 3 inches above the ground. A 6 horsepower 4-stroke gasoline engine spins a 5 bladed propeller to force air under the craft. Some air is diverted into a flexible skirt around the perimeter of the craft. The skirt is a type of air bag which helps to trap air under the craft to increase efficiency and hover higher. The higher it can hover, the better it can pass over obstacles. This is especially helpful over terrain that is not completely flat. There is a slight gap between the flexible skirt and the surface while its hovering. When hovering, the craft is virtually friction free and only requires a small thrust to move at high speeds. The craft hovers best over smooth flat surfaces. The hoverboard has been used over a variety of terrains such as pavement, dirt, grass, snow, ice and even shallow water.

The unit is propelled forward by a rear mounted thruster assembly that uses a mini 3 horsepower 2-stroke gasoline engine to spin a 14 inch ducted propeller.    The thruster produces about 20 lbs of forward thrust at full throttle. Steering is accomplished by a small movable electronic rudder mounted inside the rear thruster. The directional thrust is capable of pushing the hoverboard forward at 20+ mph.

A hand controller is held by the riders and is used to control the rudder position and engine speed and hover height. By using the hand controls, the rider can cause the hoverboard to turn left and right, speed up, slow down and stop.

In the event that the rider jumps off the hoverboard, the hand controller will simply unplug from its cable. This causes the engines to shut down and the hoverboard to stop. This prevents the hoverboard from continueing off on its own. The propeller ducts are covered with 1/4" metal mesh screens to protect the rider from the fast spinning propellers and to prevent debree from falling inside. A rubber anti-slip pad is attached to the hoverboard to allow the rider to achieve good footing traction when riding in any climate conditions.

The hoverboard is made using sandwich foam core construction and has a hard fiberglass outer shell for light weight and high strength. The unit weighs approximately 80 lbs.

More here.