13 — Questions that keep the story honest

This appendix preserves the research question map in plain form so the essay’s story does not hide the homework. Answers live in the chapters above and in the source research package.

Category and law

• When is a one-way attack UAV a munition versus an aircraft for export control and law of armed conflict?
• How do weight classes (under 250 g, Part 107, heavy UAS, passenger eVTOL) change design targets?
• What fails if passenger residual risk is treated like small UAS risk?

Mechanism

• How do fixed-pitch multirotors control attitude versus variable-pitch helicopters?
• Why does hover efficiency still favor large rotors or wings at human scale?
• When do hybrid VTOL and tilt designs beat pure multirotors?

History

• What lineage runs from 1849 balloons through Queen Bee, Radioplane, Vietnam recon, Scout, Predator/Reaper, Phantom, FPV war, and fiber FPV?

Trends

• How far did consumer price-performance fall, and where did hobby markets saturate?
• What are honest bands for range, speed, and payload by airframe class?
• How concentrated is the small-UAS supply chain, and what does that imply?

Energy and milestones

• Cell versus pack Wh/kg—what is public, what is marketing?
• When do hybrid and hydrogen beat “more battery” alone?
• What milestone table actually gates delivery, air taxi, swarm, and heavy lift?

Convergence

• Where do IoT, sensors, networks, and AI create strong versus weak coupling with flight?
• When should you move bits instead of atoms?

Swarms and defense

• What observables separate swarm from mass, salvo, or light show?
• How did EW and fiber FPV change the stack?
• What cost-exchange ratios make missile-only C-UAS unsustainable?

State of the art

• What is best-in-class separately for imaging, cargo multirotor, hybrid cargo, MALE, passenger eVTOL, and multi-agent systems?
• What did Joby’s March 2026 conforming TIA flight actually prove?

Flying cars

• Roadable versus personal eVTOL versus air taxi—definitions and failure modes?
• What did Alef’s 2023 special airworthiness allow and not allow?
• Why does capital prefer fleets to garage dual-mode craft?

Scaling bottlenecks

• Part 108 / BVLOS status versus wishful timelines?
• Delivery $/flight public bands and which routes win?
• Noise and siting as product killers?
• CFO fund versus avoid list for 2026–2028?

3D traffic and digital ATC

• Why non-parallel planar paths must meet (jams)?
• What 3D separates—and what still collides?
• UTM vs ATM; U-space USSP/CISP?
• Uber Elevate → Joby; who else builds UTM (ANRA, Indra/GuardianUTM, Thales, Airbus)?
• Why corridors return even with height freedom?

Still thin in open sources

• Pack Wh/kg on conforming passenger eVTOLs
• Part 108 final effective dates
• Audited operator delivery unit economics
• Dual-mode production road + air certificates at scale
• Counts of true adaptive lethal swarms versus industrial mass
• City-scale federated multi-operator UTM production metrics

For full secondary density and citations, see the source research ledger and references in ../drones/.