The more propellers and motors you add to a drone, the more weight it can lift. Freefly Systems' Alta 8, designed to carry heavy video equipment, has eight rotors making it strong enough to tow a surfer on a wakeboard. Say hello to the new sport of dronesurfing where waves aren't necessary.
Is this even possible? Standing on the beach the drone probably isn't strong enough to pull the surfer off his feet. But as you can see in the video, that's why he had to get a running start and hop on the wakeboard for the stunt to work.
Does a massive drone like this have enough strength to maintain the surfer's forward momentum on a low-friction lake? Without a doubt. In fact, we've seen similar stunts like this before, including a kid being pulled on a snowboard by a drone that's considerably smaller than this one.