Joby Aviation S4
Joby Aviation · United States · Air Mobility · also known as Joby S4, JAS4-1, Joby air taxi · Updated
The Joby Aviation S4, also written as the JAS4-1, is a battery-electric vertical take-off and landing air taxi built by Joby Aviation of California, in the United States. It carries a pilot on board together with up to four passengers, and it is currently in the flight-test phase of United States Federal Aviation Administration type certification rather than in commercial passenger service.
Design and capabilities
The S4 uses six electric propeller units, each with five blades, mounted around a fixed wing and tail. The units tilt so that they lift the aircraft vertically for take-off and landing and then rotate forward for wing-borne cruise, which lets the aircraft operate from a pad without a runway while still cruising like a conventional fixed-wing aeroplane. Power comes from batteries, and the design has no fuel-burning engine in its standard configuration.
Joby gives a gross weight of 2,400 kg and a service ceiling of 10,000 ft, about 3,048 m. The company quotes a speed of up to 200 mph, roughly 320 km/h, and space for four carry-on bags in addition to the occupants. Published figures put the range at up to 150 miles, about 240 km, on a single charge, and the maximum payload at 1,000 pounds, about 454 kg. Joby states cruise noise of 45 dBA measured from 500 m and 65 dBA on landing measured from 100 m.
The aircraft is flown by a pilot seated on board. Joby has also flown two derivative configurations: a hydrogen-electric S4 that flew 523 miles in June 2024 and later 561 miles without stopping, and an S4-T hybrid-electric demonstrator developed with L3Harris Technologies that first flew on 7 November 2025.
Programme status
Joby moved from subscale prototypes to full-scale uncrewed prototypes in 2017 and revealed its production vehicle configuration in January 2020. The production version was rolled out on 28 June 2023, the same date the aircraft was cleared by the FAA for flight testing. In June 2023 Joby announced a contract with the United States Air Force, and the first aircraft was delivered to Edwards Air Force Base in September 2023.
Joby's first FAA-conforming aircraft, registered N547JX, flew on 11 March 2026. That aircraft is being used for Type Inspection Authorization testing, the aircraft-level evaluation stage that precedes a type certificate. Joby has said it expects FAA pilots to begin "for credit" TIA flight testing later in 2026, and that it aims to roughly double output to four aircraft a month during 2027. No type certificate had been issued at the time of writing.
FAQ
Is it flying today? Yes, as a test aircraft. Conforming airframes are flying in the FAA's Type Inspection Authorization programme, and earlier aircraft have been delivered to the United States Air Force, but the S4 is not yet certified for paying passengers.
How many people does it carry? Five in total: one pilot and four passengers.
Does it need a runway? No. It takes off and lands vertically on its tilting propellers and then transitions to wing-borne flight.
