Joby's "Stage 4" milestone wasn't what it seemed

A version of this story that circulated in late July 2026 claimed Joby Aviation had completed Stage 4 of its FAA certification process — the last major testing hurdle before a type certificate. It hadn't. A correction published 30 July 2026 walked the claim back, and the underlying numbers explain why the mistake was an easy one to make and an important one to fix.

The FAA's certification process for a new aircraft type runs in five stages. Stage 4, "Testing and Analysis," is where a manufacturer performs the inspections, analyses and flight tests that generate the compliance data regulators use to decide whether the aircraft meets the certification basis agreed earlier in the process. It is the stage with the most flying in it, which is why reaching it reads, from the outside, like the finish line. It isn't: Stage 5 still has to process, review and formally approve everything Stage 4 produces.

As of 1 May 2026, Joby's own reporting put Stage 4 at 15% complete on its side of the ledger, with only 6% of that work formally accepted by the FAA — a meaningfully earlier position than "Stage 4 complete" implies. The company did reach a genuine milestone in November 2025, when it received Type Inspection Authorization (TIA), which marks entry into Stage 4 rather than its completion. Confusing TIA with a finished Stage 4 — or a finished Stage 4 with a type certificate — is the recurring error in how this industry's progress gets reported, and the correction on this story is a useful marker of how easily it happens even in specialist coverage.

What's left before Joby can fly paying passengers commercially in the United States is a specific, sequential list: close out the FAA's findings against the remaining Stage 4 test data, receive the aircraft's type certificate, secure FAA production approval for the factory building it, add the aircraft (which Joby designates the S4) to its own Part 135 air-carrier operating certificate, and get pilots, maintenance programmes, ground infrastructure and operating procedures individually approved. None of that is unusual for a new aircraft type; all of it takes time that a single "Stage 4 done" headline erases.

Analyst estimates cited alongside Joby's TIA milestone put the odds of full U.S. type certification by mid-2027 at 20–30%.

There is a nearer-term path that doesn't run through full FAA type certification at all. Joby, like Archer, is pursuing controlled operations under the FAA's Integration Pilot Program and a separate commercial launch in Dubai, where the regulatory approval sits with the UAE's General Civil Aviation Authority rather than the FAA. Both of those could plausibly happen within 2026. Routine, unrestricted U.S. commercial passenger service — the thing most coverage of "2026" actually means — is a different and later milestone, and nothing in Joby's own disclosures as of mid-2026 commits to it this year.

None of this is a knock on Joby's engineering progress, which by most independent accounts remains ahead of its U.S. competitors. It is a reminder that "Stage 4" is a process milestone with a precise technical meaning, not a synonym for "almost certified" — and that the gap between those two readings is exactly where a lot of eVTOL industry news goes wrong.