UK-based eVTOL developer Vertical Aerospace announced on May 19, 2026 that it has begun integration testing for its next-generation hybrid-electric propulsion system and produced the first all-electric Valo battery from its upgraded assembly line in Kemble, Gloucestershire. The two milestones together push the VX4 program one step closer to its 2028 certification target.
Hybrid-electric integration testing
The integration tests cover the company's hybrid powertrain reference architecture, in which a small turbogenerator extends the range of an otherwise all-electric VX4 by recharging the battery in cruise. Vertical sees the hybrid variant as the route to regional missions of 1,000+ kilometers, complementing the urban-air-mobility use case targeted by the baseline all-electric aircraft. Ground tests at Kemble will validate thermal management, controls and energy-management software before flight integration on a dedicated test article later in 2026.
Why the Valo battery matters
The Valo battery is Vertical's in-house lithium-ion pack engineered for the high-power, high-cycle demands of eVTOL hover and transition. Producing the first unit from the upgraded line is a manufacturing readiness signal regulators look for ahead of type certification. Vertical says the new line is designed to support series production at rates compatible with launch customer commitments from American Airlines, Japan Airlines, GOL and Bristow.
Race against Joby and Archer
The hybrid-electric and battery announcements arrive as U.S. rivals press their own programs. Joby and Archer's increasingly litigious dispute is consuming legal bandwidth on both sides, and Vertical itself remains the only European OEM to have completed a manned transition flight inside a certification framework, achieved in April 2026 under the UK Civil Aviation Authority's Design Organisation Approval regime. Eve Air Mobility is targeting transition flights this summer and Joby is on track for FAA type certification later in the year.
Path to certification
Vertical maintains a 2028 certification target with the UK CAA and is pursuing concurrent validation with EASA. Management said the manufacturing footprint at Kemble, paired with the in-sourced Valo battery, gives the company the cost and quality control it needs to ramp early commercial deliveries to launch customers. The hybrid VX4 derivative will follow on a separate certification track and is expected to address regional and emergency-services missions where range and reserves matter more than block speed.
Reporting based on coverage from FlightGlobal, Aerospace Global News, Vertical Aerospace and Aviation Today.