In this series, we set off around the world to uncover the invisible global networks and complex logistics that make it all possible. We meet the hidden army of experts working to keep the city aloft, and discover the extraordinary engineering and technology that makes it tick.

The city in the sky is set to double in size over the next two decades, and keeping it airborne is testing our ingenuity to its absolute limits. Yet despite its extraordinary rate of growth, air travel is now safer than ever before, and the series will explore how this achievement is sustained.

The series follows the arc of an actual journey: episode one, Departure, focuses on how aircraft are prepared for take-off; episode two examines what happens during flight, and episode three, Arrival, looks at what it takes to bring flights safely back down to earth.

In order to gain real insights into the nature of the global aviation network, we travel to some of its most extreme, busiest or far flung outposts. From the coldest airport in the world at Yakutsk, to the busiest (Atlanta) and the airport that is one of the most dangerous at which to land (Paro, in the Himalayas). At all of these places and more, the series meets the men and women who keep the planes in the sky.

Across the series, we uncover a fascinating world that has transformed the way we live in the 21st century. Our modern way of life would simply not be possible without the city in the sky.