According to Amazon, a future where self-flying drones zip through the sky delivering products is just around the corner. It’s a future that seems to draw closer with each new technical achievement: Drones can now take off and land on their own and even dodge stationary objects. But, as you’ll see in the video above, if you talk to the leading scientists trying to make these autonomous drones, actually enabling drones to fly on their own from take off until they arrive at their destination is a lot more complicated than it might seem.