Joby Aviation, known for its electric air taxis, is teaming up with defense giant L3Harris to develop a new gas turbine hybrid vertical takeoff and landing (VTOL) aircraft aimed at military customers.
Hybrid S4 to Offer Extended Range, Payload Capacity
The platform will be based on Joby’s existing all-electric S4 aircraft but modified to incorporate a gas turbine hybrid powertrain. L3Harris will integrate sensors, payloads, effectors, and collaborative autonomy features, and will market the aircraft to military clients, according to Joby Executive Chairman Paul Sciarra.
Targeting Contested Logistics, Counter-UAS, Electronic Warfare
The US military is seeking versatile platforms that can operate in austere environments, particularly in the Indo-Pacific. The hybrid S4 can take off and land vertically like a helicopter, but also rotate its propellers to fly like an airplane, offering increased range and speed. Potential use cases include contested logistics, counter-UAS (unmanned aerial systems), and electronic warfare, Sciarra said.
Cost-Effective Alternative to Traditional Aircraft
Sciarra said the hybrid S4 will be „significantly cheaper than a $30 million [AH-64] Apache” while offering a payload capacity of roughly 1,000 to 2,000 pounds.
Flight Tests Planned for Fall 2025
Joby plans to begin flight testing the new aircraft this fall and aims to participate in government exercises in 2026.
Leveraging Existing Infrastructure, Commercial Expertise
Joby intends to manufacture the aircraft using its existing facilities in Marina, California, and Dayton, Ohio. The partnership with L3Harris allows the company to leverage established supply chains and manufacturing expertise.
Hybrid S4 a „Next Stage” in Development
Sciarra noted that Joby previously modified and flew a hydrogen-electric powered S4 under a DoD contract, framing the collaboration with L3Harris as the „next stage” for the aircraft’s development. Maturing the vehicle’s gas turbine hybrid propulsion system and autonomy features can „feed back into the commercial market,” Sciarra said, while the scale of commercial orders can similarly benefit Pentagon buyers.
Air Force Expresses Interest in Hybrid Platforms
While Joby previously delivered its all-electric S4 to the Air Force for testing under the Agility Prime program, the service has acknowledged the limited range of all-electric vehicles for military missions and expressed interest in hybrid platforms.
eVTOL Development to Continue in Parallel
Joby plans to continue development of its all-electric eVTOL S4 alongside the hybrid platform, focusing on certification and commercialization for civilian applications.
