A High-Altitude Airship (HAA) is a type of unmanned aerial vehicle (UAV) that operates at extremely high altitudes, typically above 60,000 feet (18,288 meters). HAAs are designed to stay aloft for extended periods, often weeks or even months, and are used for a variety of applications, including communications, surveillance, and earth observation.

HAAs are typically filled with helium or hydrogen and are equipped with solar panels or fuel cells to generate power. They are designed to take advantage of the jet stream and other high-altitude winds to stay aloft and maneuver. HAAs can be used to provide communications services, such as cellular or internet connectivity, to remote or underserved areas. They can also be used for surveillance and reconnaissance, providing a persistent and wide-area view of the ground below.

One of the key benefits of HAAs is their ability to operate at high altitudes, above most weather systems and air traffic, which allows them to provide a stable and consistent platform for various applications. However, HAAs also pose significant technical challenges, including the need to withstand extreme temperatures, radiation, and weather conditions, as well as the requirement for reliable and efficient propulsion and power systems.

Examples of HAAs include the Lockheed Martin High Altitude Airship (HAA) and the Northrop Grumman Long Endurance Multi-Intelligence Vehicle (LEMV). These systems have been developed for a range of military and commercial applications, including communications, surveillance, and border patrol.