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Looks like space inside that machine for about two minutes worth of battery power .... just enough to make the video.
Or is it plugged in to a power source .... at one point in the video you can see a cord or rope being dragged along
Here is a recent "record setting" 905 feet on batteries
Watch A Record-Setting Hoverboard Flight | Popular Science
Hiller was doing this on 80 hp gasoline power in 1955
https://www.youtube.com/watch?v=W3FS3D1rCos
Which proves the old saying .... "everything was invented in the 1940's"