AALTO

AALTO HAPS Limited, trading as AALTO, is a company in Farnborough, United Kingdom, that manufactures and operates Zephyr, a solar-electric uncrewed aircraft built to fly in the stratosphere as a high-altitude platform station (HAPS). The company states it was founded in 2022, and it is a subsidiary of Airbus: Airbus Defence and Space remained the majority shareholder after outside investment was committed in 2024. AALTO calls the operating layer between conventional air traffic and low Earth orbit "Stratospace" and describes Zephyr as a dual-use craft that sits across UAV, satellite, connectivity and aviation technology.

Zephyr is a fixed-wing aircraft powered entirely by solar energy, designed to stay above 60,000 feet for weeks or months at a time and to fly through both day and night. The company cites a world-record continuous stratospheric flight of 67 days (earlier Zephyr material gives more than 64 days) and describes it as the longest unrefuelled flight and the longest duration for any uncrewed HAPS. Airbus describes the aircraft as payload agnostic. Wingspan, mass and payload capacity are not published on the company's pages.

Two service lines are offered to commercial and government customers. The first is direct-to-device mobile connectivity: Zephyr carries a 4G/5G payload, developed in Farnborough, that links to standard smartphones, intended to extend mobile network operator coverage and to restore capacity after natural disasters. The second is Earth observation, covering monitoring, tracking, sensing and detection, with Airbus's Strat-Observer service named for this role; disaster management, border protection and precision agriculture are listed use cases.

In February 2025 AALTO reported completing Zephyr's first stratospheric flight from AALTOPORT, its launch and landing site in Laikipia County, Kenya. The aircraft flew above 60,000 feet for more than 13 days carrying a direct-to-device payload, after about 18 months of regulatory work with the Kenya Space Agency and the Kenya Civil Aviation Authority.

In June 2024 a Japanese consortium led by NTT DOCOMO and Space Compass, with Mizuho Bank and the Development Bank of Japan, committed USD 100 million to AALTO through HAPS JAPAN Corporation. The plan announced with that investment was a first commercial service in Japan and global entry into service in 2026.