The variety of drones available on the market is constantly growing and so is the amount of commercial application of them. A tethered drone is another interesting one. It has a kind of rope which connects it with the ground. Thanks to the connecting line data can be send up and down between the drone and the station on the ground, and also the drone is being charged. Thanks to the solution, the tethered drones are able to fly for as long as even 220h. They are designed to be used mostly in surveillance and communication, e.g. during events such as concerts or marathons, but other usages are also tested. One of the companies developing tethered drones is CyPhy – a start-up from Massachusetts. The company was featured recently at a Bloomberg video. The commercial application of drone technology offers many possibilities, and according to our report (also cited by Bloomberg) the market is valued for USD127bn.