SION, Switzerland and SELZACH, Switzerland, April 20, 2026 /PRNewswire/ --
For Smartflyer, the delivery represents a critical step forward in the SFX1 Proof of Concept Demonstrator program, enabling the transition from component-level validation to full system integration and testing. For H55, it marks the continued integration of its certification-ready battery systems into active aircraft programs, reinforcing its position as a provider of scalable, commercially deployable electric propulsion solutions.
The newly delivered Adagio battery modules will be integrated into the SFX1 Aircraft as part of the next phase of development. This includes comprehensive system-level validation covering propulsion architecture, energy management, and other critical aircraft systems, in preparation for the upcoming ground test campaign.
At the same time, this milestone reflects the maturity and readiness of H55's product portfolio. The Adagio battery system has successfully completed all regulator-required certification tests, demonstrating its safety, reliability, and suitability for integration across a growing range of electric and hybrid-electric aircraft applications.
The SFX1 program is now entering an advanced stage of development, with integration activities intensifying across multiple workstreams. Ongoing efforts focus on coordinating installation, calibration, and test readiness to ensure a smooth transition into the next milestones. Ground testing of the SFX1 is planned for this summer, with the first flight targeted for autumn, keeping the program aligned with its development roadmap.
said Rolf Stuber, CEO of Smartflyer.
said Rob Solomon, Chief Executive Officer of H55.
H55 is a Swiss-based company specializing in certified electric propulsion and certification-grade energy storage systems for aviation. The company enables electric aviation to scale by transforming commercial lithium cells into aviation-safe Energy Storage Systems that regulators approve, insurers underwrite, and OEMs can deploy repeatedly as a certified propulsion platform across aircraft programs. This is achieved through independent cell characterization, rigorous incoming screening, redundant safety architectures, and regulator-aligned testing designed around worst-case failure scenarios.
Founded as the technological legacy of the Solar Impulse program, H55 builds on more than two decades of hands-on electric aviation experience. The company has designed, built, and flown multiple electric aircraft and has accumulated more than 2,000 hours of fully electric flight with zero battery-related incidents—providing the operational depth required to execute certification-grade programs, not merely comply with them.
H55 benefits from a strong and experienced leadership team that combines deep expertise in scaling technology companies with hands-on operational execution. Together, these capabilities support a reliable transition from certified design to repeatable series manufacturing. H55's platform-based approach, in which certification evidence compounds across programs, reduces adoption risk while facilitating the capital-efficient deployment of electric and hybrid-electric aircraft.
Smartflyer is a Switzerland-based aviation company developing the SFX1, an innovative hybrid-electric aircraft designed for sustainable pilot training. By combining advanced electric propulsion with a range extender architecture, Smartflyer aims to significantly reduce emissions and operating costs while maintaining operational flexibility. The SFX1 program is currently progressing through its Proof of Concept phase, with a strong focus on certification-ready technologies and scalable solutions.
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