Flying taxis? Don’t hold your breath

Few pieces of modern hardware have inspired as much excitement as the drone. While nonmilitary unmanned aerial vehicles (UAVs) were initially marketed as purely recreational gadgets, it has not taken long for entrepreneurs and industrial giants to seize on the endless possibilities they offer. Many are already predicting a future in which drones reshape our cities — through remote delivery of goods, airborne surveillance, or as yet unforeseen applications.
But one possibility has captured our collective imagination more than any other; the idea that drones will soon be moving people over cities en masse. Might flying taxis one day pluck us from our front gardens and delicately plop us down outside the cinema or our favorite restaurant?
Before we mentally hail the next air cab, let us consider what it would actually mean if the skies were filled with swarms of miniature helicopters ferrying people to their next destination. Though drones will have many important uses in the future, I do not believe moving people around cities will, or should, be one of them.
The dream of unmanned aerial transport is not new. When Fritz Lang created the futuristic cityscape for his groundbreaking 1927 film, Metropolis, he filled its skies with vertiginous towers and compact flying vehicles. Then, in the early 1960s, the Hanna-Barbera animation studio produced The Jetsons, a cartoon series following the escapades of a futuristic all-American family. In the opening credits the family whizzes around Orbit City in a hover car that folds up into a briefcase, which George, the family patriarch, then carries into his office. In 1982, the science-fiction blockbuster Blade Runner featured flying police cars called “spinners.”
Today, a version of such make-believe futures would seem tantalizingly within reach. Uber is investing in flying car technology. This year Airbus launched Pop.Up, a vertical takeoff and landing concept vehicle for personal mobility. And in a venture that promises “flight for all,” the German start-up Volocopter has designed the 2X, a miniature helicopter with 18 rotors that had its first test flight in Dubai last month, with a promise of full passenger service in five years.
So we will all soon be zipping around like George Jetson, right? Wrong.
First, consider the physics. Anyone who has stood near a helicopter taking off will understand that a lot of energy is required to lift a heavy object vertically into the air. Drone rotors are essentially big fans, pushing air down to create upward propulsion. There is no way to achieve lift without creating a vast amount of both noise and air disturbance.
New projects in the pipeline aim to take zipping around like George Jetson out of the realms of science-fiction and into reality, but there are practical and technological reasons for skepticism.

Carlo Ratti
Other factors that should curb our enthusiasm are more technological. Even with dramatically improved batteries extending drones’ range, the crush of vehicles needed to move large numbers of people overhead would present a daunting safety hazard. Modern cars may be dangerous, but a dead battery or a broken rotor blade in a flying taxi would cause a heavy vehicle to fall on to a densely populated area. And we still do not know whether such drones could be protected from hackers, terrorists, or other criminals, or how air traffic control systems might guide people safely.
Drones will still have a transformative impact on how future populations live, do business, and interact. Small UAVs have already proven their potential across diverse fields — from humanitarian-aid delivery to security. Drones transcend geographical barriers without the need for large-scale physical infrastructure, and can bring isolated communities into close contact with the rest of the world. In Brazil, for example, the government is deploying camera-equipped drones to inspect remote agricultural producers suspected of breaking labor laws. And drones are already monitoring air quality and providing support during health emergencies.
But urban mobility is not an appropriate application for this technology. The problems of mass transport can be fixed without taking to the skies — and long before flying taxis are even a viable alternative. With improvements to digital networks and real-time data, autonomous cars, trucks and boats can be made fast and effective enough for all our needs. And staying on the ground will obviate the need for networks of new infrastructure, like costly “vertiports.”
Society’s enduring dream of whizzing over a city in private flying cars has long captured the imagination of filmmakers — and now even some investors. For practical reasons large and small, however, it is a vision that will remain the stuff of fantasy.
• Carlo Ratti is Director of the Senseable City Lab at MIT and founder of the design firm Carlo Ratti Associati. He co-chairs the World Economic Form Global Future Council on Cities.