A longitudinal view of Joby's S4 program across FAA conformity testing, type certification, manufacturing scale-up and preparations for passenger operations, separating company-reported progress from issued regulatory approvals.
~75% — Joby-reported Stage 4 completion in its Q2 2026 Form 10-Q 20% / 10% — Joby/FAA Stage 5 progress reported as of July 31, 2026 5 aircraft flying / 12 additional aircraft in production — company-reported Q2 2026 2022 — FAA Part 135 air carrier certificate received
The S4 is a useful test of the Programs format because certification, conforming-aircraft testing, manufacturing scale-up and operating preparation are happening in parallel. Keeping those evidence streams separate prevents production activity or company stage percentages from being mistaken for regulatory approval.
FAA for-credit testing, closure of remaining compliance findings, type certification, production approval and the operating approvals required to put the S4 into passenger service.
Evidence status: Joby holds an FAA Part 135 air carrier certificate, but the S4 does not yet hold an FAA type certificate. Certification percentages and production counts below are company-reported unless explicitly described as an issued FAA approval.
Joby's S4 has moved into conforming-aircraft and final-stage compliance activity while manufacturing capacity is expanding in parallel. In its Q2 2026 filing, Joby said it had completed or substantially completed the first three stages of its own five-stage certification framework, was approximately 75% complete in Stage 4, and was progressing through Stage 5. Those stage percentages are Joby's reporting framework, not separate FAA approvals.
Joby reported in May 2026 that its first FAA-conforming aircraft for Type Inspection Authorization testing had flown and that it had completed its SR3 audit with the FAA. The company described SR3 as the third of four major reviews used to confirm that certification data and test results are being produced in the form required for final-stage testing. The existence of conforming aircraft and FAA-related testing is stronger evidence of program maturity than prototype flight hours alone, but neither constitutes type certification.
The FAA certification basis for the aircraft was agreed with Joby in 2022 and later published in final form. Joby's August 2026 shareholder material reported Stage 5 progress of 20% on the company side and 10% on the FAA side, with Stage 4 at 83% and 77% respectively as of July 31. These figures are useful for tracking Joby's own program over time; they should not be compared numerically with another manufacturer's differently defined phases.
Joby reported five electric air taxis flying and 12 additional aircraft in production in its Q2 2026 shareholder letter. It also formed a manufacturing joint venture with Toyota intended to support higher-volume production. Separately, Joby's SEC filings state that FAA production certification remains required and that the company intends to obtain it after type certification. Aircraft in production therefore should not be read as evidence that FAA production approval has been issued.
Joby received its Part 135 air carrier certificate in 2022, which allows the company to operate an on-demand air service with approved aircraft. The S4 itself still needs the applicable aircraft approvals and operating-authority additions before widespread passenger service in the United States. Joby has also pursued operations and validation pathways outside the US, including Dubai, the UK, Japan and Australia.
The decisive evidence still outstanding is closure of the remaining FAA compliance work, issuance of an S4 type certificate, production approval for the certificated design, and the operating approvals needed to place that aircraft into passenger service. Joby's disclosed schedules and launch targets are company guidance, not regulator-approved dates.
Watch for FAA-witnessed or for-credit testing milestones, closure of remaining compliance findings, any issued type certificate, subsequent production approval, and evidence that the certificated aircraft has been added to the operating framework required for passenger service.
Not investment advice. This article tracks technical, certification and operational evidence and does not recommend buying, selling or holding any security.
