Air taxi glossary
The words you’ll see on company pages and in the news, in plain English. Where a rule or regulator defines a term, we link to it. We checked every source on October 10, 2026.
Aircraft · Certification · Flying and landing · Deals and orders · Regulators
Aircraft
eVTOL
Electric vertical takeoff and landing. An aircraft that takes off and lands straight up and down using electric power. What is eVTOL?
VTOL
Vertical takeoff and landing, electric or not. Helicopters are VTOL aircraft.
Air taxi
A short passenger flight service, usually planned with small eVTOLs. See all companies.
Powered-lift
An FAA category for aircraft that lift off on engine-driven rotors or thrust and cruise on a wing. The FAA is certifying Joby’s and Archer’s aircraft this way. Source: 14 CFR 1.1 (opens in new tab) How the FAA certifies powered-lift.
Multirotor
An eVTOL with many rotors and no wing. The rotors do all the lifting, as on a large drone. Volocopter’s VoloCity has 18 rotors.
Lift + cruise
Separate rotors for takeoff and landing, a separate propeller for forward flight, and a wing for cruise. BETA’s ALIA uses this layout.
Tilt-rotor
The same propellers point up for takeoff, then tilt forward for cruise. Joby’s aircraft works this way. Archer’s Midnight tilts six of its 12 propellers. Joby vs. Archer
Autonomous
Flown without a pilot on board, either by onboard software or by a remote supervisor. Manned or autonomous?
Certification
Type certificate (TC)
The FAA’s approval of an aircraft design. It’s issued when a company shows the design meets the rules, and it’s the foundation for approvals to build and fly the aircraft. Source: FAA Order 8110.4C (opens in new tab)
Certification basis (G-1)
The exact list of rules an aircraft must meet. Joby calls its signed basis a “G-1,” an agreement with the FAA on the specific requirements for certification. Source: Joby 2025 Form 10-K (opens in new tab)
Special class and airworthiness criteria
How the FAA certifies powered-lift today. Instead of one rulebook, it publishes criteria for each design, drawn from airplane, helicopter, engine, and propeller rules. Its 2025 advisory circular offers a standard set for small electric powered-lift. Source: FAA AC 21.17-4 (opens in new tab)
TIA (Type Inspection Authorization)
An FAA authorization, issued after it reviews a company’s test results, for the official inspections and flight tests that count toward the type certificate. It comes near the end of the process. Source: FAA Order 8110.4C (opens in new tab)
Production certificate
FAA approval to build copies of a certified design. Joby plans to get one shortly after its type certificate. Source: Joby 2025 Form 10-K (opens in new tab)
SFAR (Special Federal Aviation Regulation)
A temporary FAA rule for a specific need. SFAR No. 120, now 14 CFR Part 194, covers how powered-lift pilots are trained and certified and which operating rules apply. It took effect January 21, 2025, and runs until January 21, 2035. Source: 14 CFR Part 194 (opens in new tab)
Flying and landing
Part 135
The FAA rules for on-demand and commuter air service, like charter flights. An air taxi company needs a Part 135 certificate to carry paying passengers. Joby says it got its certificate in 2022. Sources: 14 CFR Part 135 (opens in new tab), Joby 2025 Form 10-K (opens in new tab)
Vertiport
A landing site for VTOL aircraft. The FAA treats vertiports as a type of heliport, and its design guidance covers aircraft with three or more propulsors. Vertiports carry a “VTL” marking. Source: FAA Engineering Brief 105A (opens in new tab)
eIPP
The FAA’s eVTOL Integration Pilot Program. Eight projects, picked on March 9, 2026, fly test operations with state and local partners. Source: FAA, March 9, 2026 (opens in new tab) How the pilot program works.
AAM (advanced air mobility)
The umbrella term for new kinds of flight. The FAA uses it for projects that include air taxis, regional flights, cargo, medical flights, and autonomous aircraft. Source: FAA, March 9, 2026 (opens in new tab)
Deals and orders
Firm order
A signed purchase agreement. It can still depend on certification and delivery dates.
LOI (letter of intent) and preorder
A stated plan to buy. It usually isn’t binding.
MOU (memorandum of understanding)
An agreement to work together, often on a possible order or a service launch. Like an LOI, it’s usually an early step.
Deposit or pre-delivery payment
Money paid toward future aircraft. Compare every company’s orders.
Regulators
FAA
The U.S. Federal Aviation Administration. Companies in FAA certification
EASA and SC-VTOL
The European Union Aviation Safety Agency. It certifies VTOL aircraft under a special condition called SC-VTOL. Source: EASA (opens in new tab)
CAAC, ANAC, JCAB, and UK CAA
The regulators in China, Brazil, Japan, and the United Kingdom. How to read certification stage labels