Joby kicks off NYC electric air taxi demos with historic JFK flight

Battery, Range, and Powertrain Tradeoffs

• Many note current batteries (~255 Wh/kg) give poor range vs Jet-A, especially since aircraft must carry full battery weight for the whole flight.
• Some argue Joby and peers are implicitly betting on higher-density batteries (375–500 Wh/kg solid-state, etc.), though others say companies claim viability at today’s densities.
• Counterpoint: electric drivetrains are more efficient and lighter (no fuel plumbing, turbines, bleed air), with new airframe layouts (distributed propulsion, eVTOL) enabling niches despite lower specific energy.
• Skeptics emphasize fuel still provides ~order‑of‑magnitude more usable work per kg and that physics, not just airframe optimization, is the limiting factor.

Use Cases, Business Model, and Equity

• Primary near-term use case discussed is high-end airport shuttles (e.g., JFK–Manhattan), likened to early EVs: start with wealthy users, then (maybe) scale.
• Debate over how broad the market is: some note current helicopter services already attract middle- to upper-middle incomes occasionally; others see this as a 0.1% toy.
• Some would prefer tech be proven first on cargo, but others argue building a separate cargo business is a distraction.

Comparison to Trains and Ground Transit

• Large subthread argues a fast airport rail link would move far more people, cheaper and with less noise; London and Stockholm are cited as examples.
• Others respond that NYC rail construction is astronomically expensive and disruptive; extending high-speed rail to JFK could cost tens of billions.
• Existing options (subway + AirTrain, LIRR + AirTrain) are seen as slow but workable; eVTOLs win on time for a small segment, not on mass throughput.

Noise and Urban Acceptability

• Claims: significantly quieter than helicopters (e.g., ~45 dB at 500 m vs ~100 dB for helis), with higher‑frequency, less‑carrying sound from smaller, faster props.
• Firsthand media impressions say takeoff/landing are still “wince”-inducing, if much better than helicopters.
• Concern that scaling up to many flights could still be perceived as noise pollution.

Safety, Reliability, and Airspace

• Joby design reportedly tolerates up to two motor failures and can either land vertically or glide on its wing; whole-aircraft parachutes are rejected by some eVTOL developers.
• Several commenters trust helicopters more due to autorotation; uncertainty remains about eVTOL behavior in total power loss or water landings.
• Questions raised about already overworked air-traffic control handling “hundreds of tiny helicopters”; some imply eventual autonomy and automated deconfliction are needed.

Capacity, Infrastructure, and Scaling Limits

• Helipad throughput is a clear bottleneck; back-of-envelope calculations suggest serving even 10% of JFK’s hourly passenger volume would require many pads and tight scheduling.
• Pilot availability is another constraint; scaling likely pushes toward autonomous or pilotless operations.

Military and Other Applications

• Some venture optimism is attributed to potential military eVTOL/hybrid VTOL roles (logistics, range, reduced signature), beyond civilian air taxis.
• Questions raised about whether larger VTOL drones can outperform traditional helicopters for troop/cargo lift.

Technology Outlook (Hydrogen and Beyond)

• A hydrogen fuel-cell variant reportedly demonstrated >500-mile range, vs ~150 miles on batteries, but commenters highlight hydrogen’s volume and tank-weight penalties.
• Others suggest synthetic liquid jet fuel from renewables may be a more practical path to low‑carbon aviation than hydrogen or batteries for long-range.