Please take care using this demo!
The code isn't bulletproof and the Web Bluetooth API is still pretty new.
Please observe the usual caution with drone flying, as well as making sure you have a backup method of disabling the drone in the event of a bug! (A technique I have used is to raise something like a strong piece of card up towards the drone from underneath. When it detects it has been touched, the drone should shut down automatically).
You may also wish to check up on the regulations for flying drones in public in your location.
OK, now have fun!