David Brazda

I know there were some dyi experiments on YouTube about attaching LED lights to a drone. If it's open area you might give it a try although probably not entirely legal. But if it's just 15 meters height it should be fine. Even dji mavic can lift around pound payload.

The smaller the source of the light the harder the shadow. I found out that those chinese LED flashlights work wonders for casting really hard edge shadows. They are also really powerfull and as used for the background you dont have to care about CRI.