City in the Sky from Fraser Maitland on Vimeo

City in the Sky: There are around a million people airborne at any one time and keeping that number of people safely aloft depends on complex global networks and astonishing technology that stretches our ingenuity to the absolute limit. From building the world's biggest passenger plane to navigating through the busiest airport on the planet, to the perils of getting airborne in the coldest city on earth, Dallas Campbell and Dr. Hannah Fry go to extremes to get under the skin of some remarkable stories; meeting up with the air traffic controllers who are responsible for the busiest airspace in the world and revealing just what is involved in co-ordinating the 100,000 flights that cross the globe every day, while avoiding collisions.