In the section of the video on mass scaling in accordance with square-cube law, the exponent 3/2 is applied and works for SkySails’ flexible kites. The exponent 3 can be applied when the size is considered instead of the surface area.
About Makani, I calculated an exponent of 1.582 (based on surface area), or 3.164 (based on size).
About Ampyx, the exponent becomes 1.88 (based on surface area), or 3.76 (based on size).
In other words, flexible wings scale cubically (about the mass), and rigid wings beyond that.
Traditional wind turbines scale much less, and on top of that, they don’t need to fly.