Joby Aviation's type certification journey and what the first commercial air taxi actually looks like

Joby Aviation has completed Stage 4 of a five-stage FAA type certification process for its S4 electric air taxi, making it the most advanced Western eVTOL program in regulatory progress. The five-seat, six-motor aircraft targets a 100-mile range and 200 mph cruise speed, with commercial operations expected to begin in late 2026 or early 2027 in select cities including Dubai.

What Is the Joby S4?

The Joby S4 is an electric vertical takeoff and landing (eVTOL) aircraft built by Joby Aviation in Santa Cruz, California. Six tilting electric motors drive propellers that rotate from vertical (for takeoff and landing) to horizontal (for cruise flight), a concept called vectored thrust. In cruise configuration, the aircraft flies like an airplane rather than a helicopter, which is dramatically more energy efficient than sustained hovering — the same reason a Cessna burns less fuel per mile than a Robinson R44.

Key specifications:

• Five seats including the pilot
• Six independent electric motors, each driving its own propeller
• ~200 mph cruise speed
• ~100 miles design range per charge
• ~65 dBA at ground level from 100 feet altitude

Why Is Joby Certifying Under Part 23?

Joby is pursuing a Part 23 type certificate — the same regulatory basis used for a Cessna 172 or Cirrus SR22. This is neither an experimental category nor a special light-sport shortcut. It is the conventional front door of FAA aircraft certification, and the choice is strategic.

A Part 23 certificate means the aircraft fits into the existing airspace system, insurance frameworks, and pilot licensing structures. Every alternative certification category the FAA offers — light sport, experimental, primary — carries operational restrictions that would cripple an air taxi business model. Part 23 is harder and slower, but it is the only path that scales commercially.

Where Does FAA Certification Actually Stand?

As of early 2026, Joby has completed Stage 4 of five stages in the FAA type certification process. At this point, the means of compliance are locked down: Joby and the FAA have agreed on what tests must be run, what analysis must be submitted, and what the pass/fail criteria are.

The company has logged over 90,000 miles of piloted flight testing across multiple prototype and pre-production aircraft — more eVTOL flight testing than any other company worldwide. Joby has also already received Part 135 air carrier certification from the FAA, the operating certificate required to carry passengers for hire. Securing this early allows the company to build operational procedures and crew training programs while aircraft certification finishes.

How Does the Battery Technology Stack Up?

Joby uses a lithium-nickel-cobalt-manganese-oxide (NMC) battery chemistry with energy density of approximately 250–300 watt-hours per kilogram at the pack level. For context, jet fuel carries about 12,000 Wh/kg — roughly 40 times more energy-dense than current battery technology.

This energy gap is precisely why the range is 100 miles rather than 1,000, and why Joby has designed its business model around short urban and suburban routes: airport to downtown, across congested metro areas, 20- to 50-mile hops that currently take an hour or more by car. The target is replacing the taxi ride from LAX to Santa Monica, not the cross-country flight.

Why Does the Noise Profile Matter So Much?

At 65 dBA from 100 feet, the Joby S4 produces roughly 20 decibels less than a Robinson R44 helicopter at the same altitude. In acoustic terms, that means the Joby sounds approximately one-quarter as loud to the human ear.

This is not a secondary feature — it is the entire business case. Helicopter air taxi services have never scaled in cities because of noise complaints. Communities fight heliports, zoning boards deny permits, and noise curfews limit operating hours. An aircraft no louder than a conversation can operate from rooftops, parking structures, and hospital campuses where helicopters never could.

Who Are Joby’s Competitors?

• Archer Aviation (San Jose) is developing the Midnight, a similar aircraft also targeting Part 23 certification
• Lilium (Germany) was building a 36-fan ducted design but entered insolvency in late 2024 and was acquired; its future remains uncertain
• EHang (China) has received a type certificate from CAAC for the EH216, a smaller autonomous two-seat aircraft aimed at a different market segment

What separates Joby is the depth of its partnerships. Toyota has invested nearly $1 billion — not as a financial play but as a manufacturing partner, with Toyota engineers embedded in Joby’s production planning. Delta Air Lines has committed to integrating Joby flights into its booking system for airport transfers. The U.S. Air Force awarded Joby a contract under the Agility Prime program for military logistics evaluation.

Joby is also building a production facility in Marina, California, designed to eventually produce up to 500 aircraft per year. Constructing a factory before holding a type certificate is a massive financial commitment — and standard practice for serious aircraft manufacturers, since the FAA must approve production processes, quality systems, and supply chain controls under a separate Production Certificate that runs parallel to type certification.

What Are the Real Challenges?

Battery degradation. Lithium batteries lose capacity over charge cycles. An air taxi flying 20–30 flights per day accumulates cycles rapidly. Joby has disclosed little about battery replacement intervals and costs, a number that will heavily influence operating economics.

Charging infrastructure. Each landing site requires hundreds of kilowatts of charging capacity with turnaround times measured in minutes. Deploying this across a city is a civil engineering project as much as an aviation one.

Pilot supply. The S4 requires a pilot with a commercial pilot certificate and specific type rating. With airlines already competing fiercely for qualified pilots, air taxi operators will need competitive compensation for a fundamentally different flying job — high-cycle, short-hop operations in confined urban areas.

Weather sensitivity. These remain light aircraft with relatively modest wing loading. Gusty conditions, icing, and low visibility will ground the fleet. In cities like San Francisco or New York, winter months could bring significant schedule unreliability.

Public acceptance. Survey data is mixed. Most respondents say they would try an air taxi, but actual reactions to unfamiliar aircraft operating at low altitude over residential areas may differ significantly — even with reduced noise signatures.

What Is the Realistic Timeline?

Joby has publicly targeted commercial operations in late 2026 or early 2027, initially in a limited number of cities. Dubai is expected among the first markets, followed by select U.S. cities.

The timeline is aggressive but grounded in real progress. The aircraft works, the engineering is sound, and certification has advanced further than any Western competitor. The remaining questions are less about whether the S4 can fly and more about whether it can fly profitably, reliably, and at scale — business challenges as much as engineering ones.

A piloted, five-seat aircraft that takes off vertically, transitions to wing-borne cruise at 200 mph, produces less noise than a dishwasher, and emits zero direct carbon emissions was a slide deck concept a decade ago. It is now flying in California.

Key Takeaways

• Joby has completed Stage 4 of 5 in FAA type certification under Part 23, the same standard as conventional general aviation aircraft
• Over 90,000 miles of piloted flight testing make Joby the most flight-tested eVTOL program globally
• Toyota’s ~$1 billion investment and partnerships with Delta and the U.S. Air Force signal serious institutional backing
• The 65 dBA noise profile — roughly one-quarter the perceived loudness of a helicopter — is the key enabler for urban landing sites
• Battery energy density remains ~40x lower than jet fuel, constraining the business model to short urban routes of 20–50 miles
• Commercial launch is targeted for late 2026–early 2027, with Dubai and select U.S. cities first