This question already has an answer here:
An older thread already gave away the wonderful details of how the Hendo hoverboard achieves levitation, but how does it achieve its form of omni-directional control and movement?
My idea was that each engine had a gyro or gimballed mount that fed to it's artificial feedback system, and would change its pitch in response to user command, but the engines looked a bit thin to be able to hold these systems. Another concept was the use of electromagnets with varying fields, mounted throughout the board's frame.
However, I still do not understand how the boards able to create propulsion with only four engines, and what appears to be no kind of stabilizers or thrusters.