In this blog post, we’ll explore the delivery technology and flight principles of drones—which are gaining attention as the mail carriers of the future—as well as their potential for expanding internet access.
Everyone has probably had the experience at least once in their life of purchasing an item from an online store and eagerly awaiting the delivery from a mail carrier. However, in the future, we may see a world where postal workers no longer deliver these packages themselves. So who will deliver them? Drones. A drone is an unmanned aerial vehicle (UAV) that flies without a human pilot on board, controlled remotely or via an autonomous flight system. These drones have the potential to serve as the postal workers of the future. Amazon, one of the world’s largest e-commerce companies, entered the drone industry early on and has been developing “Prime Air,” a service that delivers goods via drones. Amazon conducted its first customer drone delivery in the UK in 2016 and has since expanded its actual delivery services to the U.S. and other regions. In 2026, it began offering Prime Air to customers in the UK as well. So, what is the principle behind how drones—the mail carriers of the future—fly?
To understand how drones fly, one must understand the principle by which an airfoil generates lift. An airfoil refers to the cross-sectional shape of a wing. Lift is the force acting perpendicular to the direction of travel on an object moving through a fluid. The principle behind how airplanes fly is often oversimplified using Bernoulli’s principle. Bernoulli’s equation describes the relationship between velocity and pressure in fluid flow; applying it simply, one might explain it as follows: “Because the upper surface of the airfoil is longer than the lower surface, the air flowing over the upper surface moves faster, and as a result, the pressure on the upper surface is lower than that on the lower surface, generating lift.” However, there is a significant flaw in this explanation. In particular, the assumption of “equal transit time”—that air starting simultaneously at the leading edge of the airfoil must arrive at the trailing edge at exactly the same time—fails to accurately describe the actual flow of air. In reality, the velocity and pressure distributions around the airfoil form together, and the combined aerodynamic force resulting from these generates lift. Therefore, Bernoulli’s equation and Newton’s laws of motion are not mutually exclusive explanations; rather, they can be used to describe the same aerodynamic phenomenon from different perspectives.
So how does an airfoil generate lift? It is because the airflow around the airfoil bends, causing a change in the air’s momentum, and the resulting reaction force acts on the airfoil. Specifically, on the upper surface of the airfoil, the direction of the airflow changes so that it bends downward; during this process, a pressure distribution forms, generating an upward force on the airfoil—that is, lift. When air flows along a curved path, a force is required to change the direction of that flow, which can be understood in terms of the concept of centripetal force. Centripetal force is the force that continuously redirects the motion of an object in circular motion toward the center, and its magnitude is generally expressed as m v²/r. Here, m is mass, v is velocity, and r is the radius of the curved path. Therefore, under the same conditions, the required centripetal force increases as velocity increases or the radius of the curve decreases. However, it is important to understand that the lift generated by an actual airfoil is not determined by centripetal force alone but is the result of the change in airflow direction and the pressure distribution across the entire surface of the airfoil.
Changes in the airfoil’s curvature, angle of attack, or flight speed alter the surrounding airflow and pressure distribution, which in turn affects the magnitude of lift. In particular, as an airplane’s speed increases, the airflow velocity around the airfoil generally increases as well, resulting in greater lift under the same conditions. So how does a helicopter fly without airplane wings? This is because a helicopter’s rotor blades perform a function similar to that of an airplane’s wings. A helicopter’s rotor blades have a cross-sectional shape similar to an airfoil, and when the blades rotate, a relative velocity with the air is generated, creating lift. The fact that increasing the rotor’s rotational speed generally results in greater lift can be understood using a principle similar to how lift increases as an airplane’s speed increases. So why did Amazon’s early delivery drones have eight “wings”? To be precise, they were not “wings” in the conventional sense, but rather an “octocopter” configuration using eight propellers. Using multiple propellers allows the rotation speed of each propeller to be adjusted independently, enabling precise control over the drone’s attitude and movement. For example, by adjusting the amount of thrust generated by each propeller, one can control not only the drone’s ascent and descent but also its tilt, rotation, and horizontal movement. Therefore, having more propellers provides greater freedom of movement for flight control and enhances stability.
So far, we’ve explored the principles behind drone flight from the perspectives of airfoils, airflow, and lift. Drones are no longer merely a futuristic technology but are now being utilized in actual delivery and logistics operations. Amazon conducted its first customer delivery via Prime Air in the UK in 2016 and launched the service for actual customers in the UK in 2026. Therefore, drone delivery—which was once considered a distant future prospect—is gradually becoming a reality. Meanwhile, in the past, Facebook and Google pursued plans to expand internet access using drones and invested in related companies and technologies. In 2014, Facebook launched the Connectivity Lab, which included technical staff from the British drone company Ascenta, with the aim of developing new internet delivery platforms such as aircraft and satellites. Google also acquired Titan Aerospace, a developer of high-altitude unmanned aerial vehicles, that same year and suggested the potential for using this technology to provide connectivity to regions with limited internet access. At the time, it was expected that such technology could help reduce the number of people worldwide without internet access. However, not all of these initial plans have continued unchanged to the present day. While the internet is now much more widely available than in the past, a significant digital divide still remains. According to the latest official statistics from the International Telecommunication Union (ITU), released in 2025, the number of global internet users as of 2024—based on revised estimates—stood at approximately 5.8 billion, or about 71% of the world’s population, while an estimated 2.3 billion people, or about 29% of the total population, still lacked internet access. Internet access remains relatively low, particularly in low-income countries and rural areas, prompting continued investment in various technologies and infrastructure to bridge the digital divide. The use of drones to provide internet access has also been discussed as one of these approaches. A world where drones deliver packages and provide communication infrastructure to areas difficult for people to access may be drawing closer than we think. A world powered by drones—doesn’t just the thought of it fill you with anticipation?
