How do mass drone displays work?

The Tokyo Olympic Opening Ceremony showed the spectacular potential of drones to join the party. We explain how the technology achieves the dazzling 3D images.

Photograph of drone display at Tokyo Olympics Opening Ceremony
Drones fly to form an image of the Earth in the sky over the Olympic Stadium during the opening ceremony of the Tokyo 2020 Olympic Games, in Tokyo, on 23 July 2021. Credit: Franck Fife/AFP/Getty Images