eVTOL Glossary: Urban Air Mobility Terms
Your complete guide to urban air mobility terminology. From AAM to Wing Loading, explore 40+ essential terms that define the future of electric flight and air taxi services.
AAM (Advanced Air Mobility)
Advanced Air Mobility is a broad concept encompassing the use of innovative aircraft, including eVTOLs, to transport people and cargo in urban, suburban, and rural areas. AAM extends beyond urban environments to include regional and intercity routes. NASA and the FAA are leading AAM initiatives in the United States, with the goal of integrating these new aircraft into the national airspace system.
ALIA (BETA Technologies Aircraft)
The ALIA is a fixed-wing eVTOL aircraft developed by BETA Technologies. The ALIA CX300 features a conventional wing design with a 250-mile range, making it one of the longest-range electric aircraft in development. BETA has secured partnerships with UPS for cargo delivery and United Therapeutics for organ transport. The aircraft is targeting FAA type certification in early 2026.
Archer Aviation / Midnight
Archer Aviation is a publicly traded eVTOL manufacturer developing the Midnight aircraft, a piloted electric air taxi designed for urban trips of approximately 20 to 50 miles. Midnight features a tilt-rotor configuration with 12 motors and is in the final stages of FAA type certification. Archer has partnerships with United Airlines and was named the official air mobility provider for the LA 2028 Olympics.
Autonomous Flight
Autonomous flight refers to aircraft operations conducted without a human pilot on board, relying instead on artificial intelligence, sensors, and automated systems for navigation, obstacle avoidance, and decision-making. EHang has received certification for autonomous passenger operations in China. Wisk Aero is pursuing FAA certification for fully autonomous air taxis in the United States, with most experts expecting widespread autonomous eVTOL operations by 2028 to 2032.
Battery Energy Density
Battery energy density measures the amount of energy stored per unit of weight, typically expressed in watt-hours per kilogram (Wh/kg). Current lithium-ion batteries used in eVTOLs achieve approximately 250 to 300 Wh/kg. Higher energy density enables longer range and greater payload capacity. Advances in solid-state and lithium-sulfur battery technologies could push densities beyond 400 Wh/kg, significantly improving eVTOL performance and economics.
BVLOS (Beyond Visual Line of Sight)
BVLOS refers to drone or aircraft operations conducted beyond the visual line of sight of the remote pilot or operator. The FAA released the Part 108 BVLOS NPRM in January 2026, establishing performance-based regulations for UAS operations beyond visual range. BVLOS capability is critical for eVTOL and drone delivery operations, enabling autonomous or remotely supervised flights over extended distances.
CAAC (Civil Aviation Administration of China)
The CAAC is China's national aviation regulatory authority, equivalent to the FAA in the United States. CAAC became the first regulator in the world to issue a type certificate for a passenger-carrying eVTOL when it certified the EHang EH216-S in 2023. CAAC has established special conditions for both piloted and autonomous eVTOL operations and is developing regulations for large-scale urban air mobility services in Chinese cities.
Certification / Type Certificate
A type certificate is a government-issued document certifying that a specific aircraft design meets all applicable airworthiness standards and is safe for commercial operations. The certification process for eVTOLs typically takes 5 to 8 years and involves thousands of individual test points covering structural integrity, propulsion, flight controls, and crashworthiness. Both the FAA and EASA require demonstration of a catastrophic failure rate no greater than one in a billion flight hours.
CRI (Certification Review Item)
A Certification Review Item is a formal document used in the EASA certification process to address specific technical or regulatory issues that arise during type certification. CRIs define the certification basis, means of compliance, and any special conditions applicable to novel aircraft designs like eVTOLs. Each CRI undergoes review and approval by the certification authority before the aircraft can proceed through the certification process.
DAL (Design Assurance Level)
Design Assurance Level is a classification system used in aviation software and hardware development that defines the rigor of design, testing, and verification required based on the criticality of the system. DAL ranges from Level A (catastrophic failure consequences, most rigorous) to Level E (no safety effect, least rigorous). eVTOL flight-critical systems such as fly-by-wire controls and battery management systems typically require DAL-A or DAL-B assurance.
DEP (Distributed Electric Propulsion)
Distributed Electric Propulsion is an aircraft design approach that uses multiple small electric motors spread across the airframe instead of a few large engines. DEP offers several advantages for eVTOL design including redundancy (if one motor fails, others compensate), reduced noise, improved efficiency, and greater design flexibility. Most eVTOL aircraft use between 6 and 18 individual electric motors in various configurations.
EASA (European Union Aviation Safety Agency)
EASA is the European Union's aviation safety regulator, responsible for certifying aircraft and overseeing aviation safety across EU member states. EASA published SC-VTOL, a dedicated Special Condition for VTOL aircraft certification, with Basic and Enhanced categories. The Enhanced category, required for commercial passenger operations over congested areas, demands a catastrophic failure rate of 10⁻⁹ per flight hour. Volocopter and Lilium have been among the leading EASA applicants.
eIPP (eVTOL Integration Pilot Program)
The eVTOL Integration Pilot Program is an FAA initiative designed to facilitate the integration of eVTOL aircraft into the national airspace. The program partners with local communities and operators to conduct pilot projects that test operational concepts, infrastructure requirements, and community acceptance. eIPP helps the FAA gather real-world data to inform rulemaking and policy decisions for urban air mobility.
EIS (Entry Into Service)
Entry Into Service refers to the date when an aircraft first begins commercial passenger or cargo operations. For eVTOL companies, EIS requires completion of type certification, production certification, operator certification, infrastructure readiness, and pilot training. As of 2026, EHang has achieved EIS in China, while Joby Aviation and Archer Aviation are targeting EIS in 2026 to 2027 pending FAA certification.
Electric Propulsion
Electric propulsion uses electric motors powered by batteries, hydrogen fuel cells, or hybrid-electric systems to drive aircraft propellers or rotors. Compared to traditional combustion engines, electric propulsion offers lower noise levels, zero direct emissions, fewer moving parts, reduced maintenance costs, and the ability to distribute power across multiple motors. Battery-electric is the most common approach for eVTOLs, though some designs use hybrid-electric or hydrogen fuel cell systems for extended range.
eVTOL (Electric Vertical Takeoff and Landing)
eVTOL stands for Electric Vertical Takeoff and Landing, describing aircraft that use electric power to take off and land vertically like a helicopter but fly more efficiently using wings or other lift surfaces. eVTOLs are designed to carry passengers or cargo for urban and regional trips, offering a quieter, cleaner, and more affordable alternative to helicopters. Over 1,000 eVTOL concepts are in development worldwide, with leading companies including Joby Aviation, Archer Aviation, and EHang.
FAA (Federal Aviation Administration)
The FAA is the United States federal agency responsible for regulating civil aviation, including the certification and oversight of eVTOL aircraft. The FAA is certifying eVTOLs under an adapted Part 21 airworthiness standard, creating a new powered-lift aircraft category. In February 2026, Congress introduced the Aviation Innovation and Global Competitiveness Act to accelerate FAA certification processes with 270-day response targets for issue paper reviews.
FBO (Fixed-Base Operator)
A Fixed-Base Operator is a commercial business granted the right to operate at an airport, providing services such as fueling, hangar rental, aircraft parking, maintenance, and passenger handling. As eVTOL operations expand, existing FBOs may serve as early vertiport locations, leveraging their existing infrastructure, airside access, and operational expertise. Some FBOs are already planning dedicated eVTOL facilities.
Fly-by-Wire
Fly-by-wire is a flight control system that replaces traditional mechanical linkages between the pilot's controls and the aircraft's control surfaces with electronic signals processed by flight computers. Nearly all eVTOL aircraft use fly-by-wire systems, which enable advanced stability augmentation, envelope protection, and the precise motor control required for distributed electric propulsion. These systems are critical for safe transition between vertical and horizontal flight modes.
Geofencing
Geofencing is the use of GPS or other location technologies to create virtual boundaries that restrict or enable aircraft operations within defined geographic areas. In urban air mobility, geofencing will be used to keep eVTOLs within approved flight corridors, prevent operations in restricted airspace, and enforce altitude limits. Geofencing is a key component of UTM systems that will manage eVTOL traffic at scale.
HEMS (Helicopter Emergency Medical Services)
Helicopter Emergency Medical Services use helicopters for emergency medical transport, including air ambulance operations. eVTOL aircraft are being considered as future HEMS platforms because of their lower operating costs, reduced noise, and ability to operate from smaller landing pads. Several eVTOL manufacturers are designing aircraft variants specifically for medical transport applications, with the potential to dramatically expand access to emergency air medical services.
Hover Flight
Hover flight is the phase of VTOL operations where the aircraft maintains a stationary position in the air, typically during takeoff and landing. Hover is the most energy-intensive phase of eVTOL flight, consuming significantly more battery power than forward cruise flight. eVTOL designers optimize their aircraft to minimize time spent in hover while ensuring safe and stable vertical operations in varying wind conditions.
Joby Aviation / S4
Joby Aviation is a leading eVTOL company developing the S4, a five-seat piloted air taxi with a tilt-rotor design and six electric motors. The S4 has a range of approximately 150 miles and a top speed of 200 mph. Joby is the furthest along in the FAA type certification process at approximately 70% completion and is backed by Toyota, which has 200 employees embedded with the company. Joby is targeting commercial launch in Dubai in Q2 2026.
Lift+Cruise
Lift+Cruise is an eVTOL configuration that uses separate sets of motors for vertical lift and forward cruise flight. Vertical lift motors are mounted on top of the aircraft and engage during takeoff and landing, while separate pusher or tractor propellers provide forward thrust during cruise. This design simplifies the transition between vertical and horizontal flight but adds weight from the dedicated lift motors that are unused during cruise.
LiDAR (Light Detection and Ranging)
LiDAR is a remote sensing technology that uses laser light pulses to create detailed three-dimensional maps of the surrounding environment. In eVTOL applications, LiDAR sensors are used for obstacle detection, terrain mapping, precision landing, and autonomous navigation. LiDAR is a critical sensor technology for enabling safe autonomous flight operations, particularly in urban environments with complex obstacle environments.
Means of Compliance (MOC)
Means of Compliance are the specific methods, tests, analyses, and documentation that an applicant uses to demonstrate that their aircraft design meets the applicable certification requirements. EASA published MOC-2 providing detailed technical standards for VTOL aircraft certification. Each airworthiness requirement can have multiple acceptable means of compliance, and applicants may propose alternative methods subject to regulatory approval.
Multirotor
A multirotor is an aircraft design that uses three or more rotors for lift and propulsion. In the eVTOL context, multirotor designs like EHang's EH216-S use multiple fixed-pitch propellers for vertical flight only, without wings for forward cruise. While simpler mechanically, pure multirotor designs have limited range and speed compared to winged configurations. They are best suited for short urban trips of 10 to 30 kilometers.
NASA AAM (National Mission)
NASA's Advanced Air Mobility mission is a research and development program focused on enabling safe, sustainable, and accessible air transportation. NASA conducts flight testing, develops airspace management concepts, advances electric propulsion technology, and collaborates with industry and the FAA to establish standards for urban and regional air mobility. NASA's AAM National Campaign conducts flight demonstrations and simulation exercises across the United States.
OEM (Original Equipment Manufacturer)
In the eVTOL industry, an OEM is a company that designs and manufactures eVTOL aircraft. Major eVTOL OEMs include Joby Aviation, Archer Aviation, BETA Technologies, EHang, Vertical Aerospace, and Wisk Aero. OEMs are responsible for obtaining type certificates and production certificates from regulatory authorities. Some operators like Blade Air Mobility plan to operate aircraft from multiple OEMs.
Part 135 (Air Carrier Certificate)
Part 135 refers to the section of the United States Federal Aviation Regulations governing commuter and on-demand air carrier operations. eVTOL companies planning to operate commercial passenger services in the United States must obtain a Part 135 certificate, which requires demonstration of operational control, maintenance programs, pilot training, safety management systems, and financial fitness. The Part 135 certification process typically takes 12 to 24 months.
Powered Lift
Powered lift is the FAA's official aircraft category designation for eVTOL aircraft that are capable of both vertical and horizontal flight. This new category was created specifically to address the unique characteristics of eVTOL aircraft that do not fit neatly into existing fixed-wing airplane or rotorcraft categories. The FAA published a Special Federal Aviation Regulation establishing pilot training and certification requirements for powered-lift aircraft.
Production Certificate
A production certificate is regulatory approval authorizing a manufacturer to produce aircraft in quantity under an approved quality control system. After receiving a type certificate, an eVTOL manufacturer must obtain a production certificate before delivering aircraft for commercial use. The production certificate ensures that every aircraft produced matches the type-certified design and meets all quality standards.
Range
Range refers to the maximum distance an eVTOL aircraft can fly on a single battery charge, accounting for regulatory reserves and typical mission profiles. Current eVTOL ranges vary from approximately 20 miles for urban multirotor designs to over 250 miles for fixed-wing configurations like the BETA ALIA. Range is one of the most critical performance metrics for eVTOL commercial viability, directly affecting which routes and markets an aircraft can serve.
SFAR (Special Federal Aviation Regulation)
A Special Federal Aviation Regulation is a temporary or specific regulation issued by the FAA to address unique circumstances not adequately covered by existing rules. The FAA published an SFAR to establish pilot training and certification requirements for the new powered-lift aircraft category, covering ground school curriculum, simulator requirements, flight time minimums, and practical test standards for eVTOL pilots.
Tilt-Rotor
A tilt-rotor is an eVTOL configuration where the rotors or propellers physically tilt between vertical and horizontal orientations. During takeoff and landing, rotors point upward to provide vertical lift. In cruise flight, they tilt forward to act as propellers, with the wings providing aerodynamic lift. Joby Aviation's S4 and Archer's Midnight both use tilt-rotor designs, which offer excellent efficiency in both hover and cruise flight.
Transition Flight
Transition flight is the phase when an eVTOL aircraft converts between vertical hover mode and horizontal cruise mode. During transition, the aircraft accelerates and shifts from rotor-borne to wing-borne flight (or vice versa). This is one of the most complex and safety-critical phases of eVTOL operations, requiring precise coordination of multiple motors, control surfaces, and flight control algorithms. Extensive flight testing during transition is a major component of type certification.
Type Certificate
A type certificate is the formal regulatory approval issued by an aviation authority (FAA, EASA, CAAC) confirming that an aircraft design meets all applicable airworthiness, noise, and emissions standards. Obtaining a type certificate is the single most important regulatory milestone for any eVTOL company, as commercial operations cannot begin without it. The process involves years of design reviews, ground testing, and flight testing across thousands of individual compliance items.
UAM (Urban Air Mobility)
Urban Air Mobility refers to the use of aircraft, primarily eVTOLs, for passenger and cargo transportation within urban and suburban areas. UAM encompasses the vehicles, infrastructure (vertiports), airspace management systems, and regulatory frameworks needed to enable on-demand air transportation in cities. The UAM market is projected to reach $30 billion by 2030, with cities like Dubai, Los Angeles, and Singapore among the first to launch commercial services.
UTM (Unmanned Traffic Management)
Unmanned Traffic Management is a system for managing drone and eVTOL traffic in low-altitude airspace, separate from traditional air traffic control. The FAA's Part 108 BVLOS rule released in January 2026 establishes UTM third-party services that will provide airspace management, conflict detection, and traffic coordination for eVTOL and drone operations. UTM is essential for enabling safe, high-density eVTOL operations in urban environments.
Vertiport / Vertistop / Vertipad
A vertiport is a facility designed for eVTOL takeoff, landing, passenger processing, and charging. A vertistop is a smaller, simpler facility with fewer amenities, while a vertipad is just the landing surface itself. Vertiport design standards are being established by the FAA (Engineering Brief 105) and EASA, covering pad dimensions, obstacle-free surfaces, fire suppression, charging infrastructure, and passenger handling. Vertiport networks are essential infrastructure for scaling urban air mobility services.
VTOL (Vertical Takeoff and Landing)
VTOL stands for Vertical Takeoff and Landing, describing any aircraft capable of taking off and landing vertically without a runway. Traditional VTOL aircraft include helicopters and tiltrotor aircraft like the V-22 Osprey. eVTOL is a subset of VTOL that specifically uses electric propulsion. The ability to take off and land vertically enables operations from small landing pads in urban areas where runway space is unavailable.
Wisk Aero / Gen 6
Wisk Aero, a Boeing company, is developing the Generation 6, a fully autonomous eVTOL air taxi designed to operate without a pilot on board. The Gen 6 features a lift+cruise configuration with 12 lift motors and a rear pusher propeller. Wisk is pursuing the first FAA type certificate for an autonomous passenger-carrying aircraft, with expected certification around 2028. The autonomous approach eliminates pilot costs but faces a longer regulatory pathway.
Wing Loading
Wing loading is the ratio of an aircraft's total weight to its wing area, typically measured in pounds per square foot or kilograms per square meter. Lower wing loading results in slower stall speeds, shorter takeoff distances, and better low-speed handling, but higher drag at cruise speeds. eVTOL designers must balance wing loading to optimize for both efficient cruise flight and safe transition between vertical and horizontal flight modes.
Frequently Asked Questions
Answers to the most commonly searched eVTOL and urban air mobility questions.
What does eVTOL stand for?
eVTOL stands for Electric Vertical Takeoff and Landing. It describes aircraft that use electric power to take off and land vertically like a helicopter but fly more efficiently using wings or other lift surfaces. eVTOLs are designed to carry passengers or cargo for urban and regional trips, offering a quieter, cleaner, and more affordable alternative to helicopters. Over 1,000 eVTOL concepts are in development worldwide.
What is a vertiport?
A vertiport is a facility designed for eVTOL aircraft takeoff, landing, passenger processing, and battery charging. Vertiport design standards are being established by the FAA through Engineering Brief 105 and EASA through their Prototype Technical Design Specifications. Requirements cover landing pad dimensions, obstacle-free approach surfaces, fire suppression systems, charging infrastructure, and passenger handling. Smaller variants include vertistops (basic facilities) and vertipads (landing surfaces only).
What is urban air mobility?
Urban Air Mobility (UAM) refers to the use of aircraft, primarily eVTOLs, for passenger and cargo transportation within urban and suburban areas. UAM encompasses the vehicles, infrastructure such as vertiports, airspace management systems, and regulatory frameworks needed to enable on-demand air transportation in cities. The UAM market is projected to reach $30 billion by 2030, with cities like Dubai, Los Angeles, and Singapore among the first to launch commercial services.
What is the difference between eVTOL and a drone?
While both eVTOLs and drones use electric propulsion and can take off vertically, eVTOLs are specifically designed to carry human passengers and are subject to far more rigorous safety and certification requirements. Drones are typically smaller, unmanned aircraft used for cargo delivery, surveillance, photography, and agriculture. eVTOLs must meet the same catastrophic failure rate standards as commercial airliners, requiring years of certification testing.
How much will an eVTOL air taxi ride cost?
Industry projections estimate initial eVTOL air taxi fares at approximately $3 to $5 per passenger mile, comparable to current ride-sharing services like Uber Black. As fleets scale and autonomous operations reduce pilot costs, fares are expected to decrease to $1 to $2 per mile by the early 2030s. A typical 30-mile urban air taxi trip could cost between $50 and $150 at launch, decreasing significantly as the industry matures.
Are eVTOL aircraft safe?
eVTOL aircraft are being certified to the same safety standards as commercial airliners, requiring a catastrophic failure rate of no more than one in a billion flight hours. They feature redundant electric motors (typically 6 to 18), fly-by-wire flight controls, battery management systems with multiple safety layers, and full aircraft parachute systems. The FAA and EASA certification processes ensure comprehensive safety validation through years of design review, ground testing, and flight testing.
What is AAM (Advanced Air Mobility)?
Advanced Air Mobility is a broad concept encompassing the use of innovative aircraft, including eVTOLs, for passenger and cargo transportation across urban, suburban, and rural areas. AAM extends beyond Urban Air Mobility to include regional and intercity routes. NASA and the FAA are leading AAM initiatives in the United States, conducting research, flight demonstrations, and developing the airspace management frameworks needed to safely integrate these new aircraft.
When will eVTOL air taxis be available?
The first commercial eVTOL air taxi services are expected to launch between 2026 and 2027. EHang is already operating commercially in China with its autonomous EH216-S. Joby Aviation is targeting commercial launch in Dubai in Q2 2026, and Archer Aviation plans to begin operations in Los Angeles. Wider availability in multiple cities is expected by 2028 to 2030, with autonomous operations potentially beginning around 2030 to 2032.
What is a type certificate for eVTOL?
A type certificate is a government-issued document certifying that a specific eVTOL aircraft design meets all applicable airworthiness standards and is safe for commercial operations. The certification process typically takes 5 to 8 years, involving thousands of individual test points covering structural integrity, propulsion reliability, flight controls, electrical systems, and crashworthiness. Both the FAA and EASA require a catastrophic failure rate of no more than one in a billion flight hours.
How far can an eVTOL fly on one charge?
Current eVTOL ranges vary significantly by design type. Urban multirotor designs like the EHang EH216-S have ranges of approximately 20 to 35 kilometers. Tilt-rotor designs like Joby's S4 can fly about 150 miles on a single charge. Fixed-wing eVTOLs like BETA's ALIA CX300 achieve the longest ranges at over 250 miles. Range depends on battery energy density, aircraft weight, flight profile, and weather conditions.
Explore More
Dive deeper into the world of eVTOL and urban air mobility with these resources.
eVTOL Regulations
FAA, EASA, and global certification frameworks for eVTOL aircraft.
eVTOL Companies
Profiles and analysis of leading eVTOL manufacturers and operators.
Certification Tracker
Real-time tracking of eVTOL type certification progress worldwide.
eVTOL Aircraft
Compare specifications, range, speed, and design of eVTOL aircraft models.
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