Air Transportation Industry Terminology

A-CDM (Airport Collaborative Decision Making)

Multi-stakeholder process at airports that shares real-time data (e.g., Target Off-Block Time, deicing status) among airlines, ATC, ground handlers, and the airport to optimize turnarounds, reduce delays, and improve predictability.

'Under A-CDM, we updated the TOBT to 12:25 to keep our sequence'; 'A-CDM cut our average taxi-out by 4 minutes'; 'The A-CDM milestone alerts flagged a late refuel and avoided a gate conflict.'

ADS-B (Automatic Dependent Surveillance–Broadcast)

GPS-based surveillance where aircraft broadcast their position and velocity to ground stations and other aircraft, improving situational awareness and enabling more efficient separation.

'ADS-B Out is mandated in most US controlled airspace'; 'We relied on ADS-B coverage over the Gulf when radar was limited'; 'Upgrading the fleet to ADS-B improved traffic flow on oceanic routes.'

AOG (Aircraft on Ground)

Operational status when an aircraft is grounded by a technical issue and cannot fly, triggering urgent maintenance and logistics actions.

'Declare AOG and initiate the spare-parts courier'; 'We have an AOG due to a hydraulic leak on tail N12345'; 'AOG recovery is 6 hours; start passenger reaccommodation.'

APU (Auxiliary Power Unit)

Small turbine in the tail that supplies electrical and pneumatic power on the ground (and sometimes in flight) for systems, air conditioning, and engine start.

'Start the APU at the gate for packs and power'; 'APU MEL deferred, so we need GPU and PCA at departure'; 'Shutdown the APU to save fuel during an extended ground delay.'

ASM (Available Seat Mile)

Capacity metric equal to seats offered multiplied by miles flown; the metric equivalent is ASK (available seat kilometer).

'ASMs grew 8% year over year on international routes'; 'Pulling capacity reduced unprofitable ASMs and improved margins'; 'Matching ASMs to demand stabilized load factor.'

ATC (Air Traffic Control)

Service that separates aircraft and manages traffic flows in controlled airspace and at airports.

'ATC issued a ground delay program for SFO'; 'Expect a reroute from ATC to avoid convective weather'; 'ATC spacing added 20 minutes to our block time.'

ATM (Air Traffic Management)

Broader system that includes ATC plus airspace design, flow management, and capacity planning (e.g., EUROCONTROL network measures, NextGen).

'Network ATM constraints limited peak-hour arrivals'; 'PBN and Data Comm are key ATM modernization elements'; 'Cross-border ATM coordination mitigated the sector staffing shortfall.'

BASA (Bilateral Air Services Agreement)

Treaty between countries that sets traffic rights, frequencies, designated carriers, and other commercial freedoms; open-skies BASAs liberalize these terms.

'The BASA allows seven weekly frequencies with widebodies'; 'Open-skies BASA removed pricing and capacity caps'; 'EASA–FAA BASA enables mutual recognition of maintenance approvals.'

Belly cargo

Freight carried in the lower hold of passenger aircraft, competing with baggage and weight limits.

'Belly capacity shrank when we upgauged to smaller narrowbodies'; 'Transpac belly cargo yields remained strong'; 'Weight restrictions forced us to prioritize bags over belly freight.'

Block time

Elapsed time from pushing back at origin gate to arriving at destination gate, used for scheduling, crew pay, and performance metrics.

'We padded block times to improve OTP'; 'Crew pay is often tied to block hours'; 'Headwinds pushed actual block time above plan.'

CASM (Cost per Available Seat Mile)

Unit cost metric equal to operating costs divided by ASMs; often tracked both including and excluding fuel (ex-fuel CASM).

'Ex-fuel CASM fell 3% after fleet densification'; 'Longer stage lengths generally reduce CASM'; 'CASM is a core financial KPI for airlines.'

Code-share

Commercial arrangement where one airline sells seats under its code on a flight operated by another carrier, extending network reach.

'AA123 is a code-share on a BA-operated flight'; 'Code-shares enable through-ticketing and baggage transfer'; 'Revenue on code-share segments is prorated between partners.'

Crew Duty Time (FTL)

Regulatory limits on flight and duty hours to manage fatigue risk; schedules must respect maximum duty periods, rest requirements, and extensions.

'Crew goes illegal at 22:15 under FTL rules'; 'We planned a split duty to extend limits lawfully'; 'Buffers were added to protect FTL compliance during winter ops.'

Deicing/Anti-icing

Removal and prevention of ice and snow using fluids (e.g., Type I for deicing; Type II/IV for anti-icing), governed by holdover time tables and procedures.

'We applied Type I then Type IV due to freezing rain'; 'Holdover time expires at 10:20'; 'Deicing queue caused a bank-wide departure delay.'

Dispatch (Flight Operations Control)

Licensed dispatchers in the operations control center plan, release, and monitor flights (routes, fuel, weather, alternates) jointly with the captain.

'Dispatcher released the flight with AUS as the alternate'; 'Ops Control added extra fuel for potential reroutes'; 'Part 121 requires dispatcher–pilot joint responsibility.'

Dry lease

Aircraft lease without crew, maintenance, or insurance; lessee operates the aircraft on its AOC. Contrast with a wet lease (ACMI), which includes crew and support.

'We took two A320s on a 6-year dry lease'; 'Dry lease assets appear on the balance sheet under ROU'; 'Regulators must add dry-leased aircraft to our AOC.'

EASA (European Union Aviation Safety Agency)

EU regulator that issues rules, approvals, airworthiness directives, and certifications.

'EASA issued an AD affecting our A320 fleet'; 'Part-66 licensure is required for certifying staff'; 'EASA validated the type certificate for the new variant.'

EFB (Electronic Flight Bag)

Tablet or integrated device that hosts manuals, charts, performance tools, and operational apps, replacing paper in the cockpit.

'The EFB provides runway analysis and weight & balance'; 'Class 1 EFBs are approved under our MEL procedures'; 'Chart updates are pushed to EFBs before the morning bank.'

ETOPS/EDTO (Extended Operations)

Regulatory framework allowing extended-range operations beyond a defined single-engine diversion time; expressed in minutes (e.g., ETOPS 180) and requires additional equipment, planning, and maintenance controls.

'This North Atlantic routing needs ETOPS 180'; 'We carried extra ETOPS fuel and survival equipment'; 'EDTO terminology is used more broadly in some regions.'

FAA (Federal Aviation Administration)

US aviation regulator responsible for certification, operations regulations, airspace, and oversight.

'FAA Part 121 governs US scheduled carriers'; 'The FAA issued a NOTAM closing runway 28R'; 'We obtained an FAA STC for the cabin retrofit.'

FFP (Frequent Flyer Program)

Loyalty program awarding miles/points and elite status benefits, often monetized via co-branded credit cards and partners.

'The FFP drives high-yield corporate share'; 'We devalued the award chart to manage costs'; 'Co-brand economics are a major FFP revenue source.'

Fifth Freedom Rights

Traffic rights allowing an airline to carry revenue passengers or cargo between two foreign countries on a service that originates/terminates in its home country.

'Emirates exercises fifth freedom on JFK–MXP'; 'We sought fifth-freedom beyond rights via India'; 'Fifth-freedom flights can stimulate local markets but face incumbent pushback.'

FMS (Flight Management System)

Avionics system that integrates navigation databases, performance data, and automation to manage lateral/vertical profiles and fuel/time predictions.

'Load the RNAV SID into the FMS'; 'FMS shows top of descent at 12:43Z'; 'We reprogrammed the FMS after a late runway change.'

Fuel hedging

Use of derivatives (swaps, options) to lock in future jet fuel costs and reduce volatility, subject to basis risk and hedge accounting rules.

'We hedged 60% of next quarter at $85/bbl'; 'Hedge losses offset lower spot prices this year'; 'Crack spread changes created basis risk in the hedge.'

GDS (Global Distribution System)

Technology platforms (e.g., Sabre, Amadeus, Travelport) used by agencies and corporates to shop and book air content; now evolving with NDC connectivity.

'We implemented NDC offers in the GDS'; 'Corporate bookings still flow via the GDS channel'; 'A GDS surcharge nudged traffic to direct sales.'

Ground handling

Passenger, ramp, and baggage services supporting turnarounds, performed in-house or via third-party handlers under SLAs.

'We outsource ground handling at outstations'; 'The handler missed SLA on baggage delivery'; 'Ramp staffing shortages hurt on-time departures.'

Ground stop

ATC action that temporarily halts departures to a specific airport or airspace due to capacity constraints, weather, equipment outages, or security events.

'DEN is in a ground stop for thunderstorms'; 'Expect a national ground stop during the NOTAM outage'; 'Hold aircraft at the gate until the ground stop lifts.'

Hub-and-spoke

Network model concentrating traffic at hubs to enable connections and economies of scope, often organized into banks or waves.

'We banked the hub to maximize connections'; 'The 0900 wave feeds transatlantic departures'; 'A new focus city complements our hub-and-spoke network.'

IATA (International Air Transport Association)

Global trade association for airlines that sets standards (ticketing, interline, safety programs) and runs financial settlement systems (e.g., BSP, CASS).

'We adopted IATA’s NDC standard for offers/orders'; 'IATA 2-letter codes identify marketing carriers'; 'We passed our IATA dangerous goods training audit.'

ICAO (International Civil Aviation Organization)

UN specialized agency that sets global aviation standards and recommended practices (SARPs) via Annexes, including safety, operations, and environmental schemes like CORSIA.

'ICAO Annex 14 covers aerodromes'; 'ICAO 3-letter airline and 4-letter airport identifiers are standard'; 'CORSIA offsets apply per ICAO guidelines.'

IFR (Instrument Flight Rules)

Set of rules allowing flight by reference to instruments in controlled airspace and low visibility, with specific fuel, alternate, and separation requirements.

'We filed IFR due to low ceilings'; 'IFR reserves include contingency and alternate fuel'; 'IFR separation increased spacing in the center.'

ILS (Instrument Landing System)

Precision approach system using localizer and glideslope; categories (CAT I/II/III) define minima and autoland capability.

'We shot a CAT III ILS to minimums'; 'With the ILS out, we briefed the RNAV approach'; 'A NOTAM reported the glideslope unreliable.'

Interline

Commercial agreements letting carriers sell and ticket itineraries across each other, transfer baggage, and settle revenues through clearing houses.

'We interline with regional partners for feed'; 'Interline e-tickets simplify connections for customers'; 'Without interline, separate PNRs and no through-check apply.'

Jet A-1 (Aviation turbine fuel)

Kerosene-based jet fuel widely used outside the US, with a lower freeze point than Jet A; logistics and quality control are critical for safety.

'International stations uplift Jet A-1'; 'The Jet A-1 freeze point supports high-altitude ops'; 'Plan for spec differences between Jet A and Jet A-1.'

Joint Venture (ATI JV)

Antitrust-immunized revenue-sharing alliance that allows partner airlines to coordinate schedules, pricing, and capacity on specific markets.

'The transatlantic JV aligns fares and inventory'; 'JV partners pool and share revenue by agreed formula'; 'Regulators review market power before granting ATI.'

KPI (Key Performance Indicator)

Quantitative measure used to track operational, financial, or customer outcomes (e.g., OTP, CASM, RASM, NPS, safety rates).

'OTP and NPS are headline KPIs'; 'We monitor CASM and RASM monthly'; 'Safety KPIs include audit findings and closure rates.'

Landing fees

Airport charges for runway use, typically based on MTOW and sometimes time of day or noise category; a key part of airport aeronautical revenue.

'We negotiated lower landing fees for new routes'; 'Charges scale with MTOW and aircraft type'; 'Peak-period fees are higher under the tariff.'

LCC (Low-cost carrier)

Business model emphasizing low unit costs via high utilization, single-type fleets, point-to-point networks, and unbundled ancillary revenues.

'As an LCC we target quick turnarounds and high daily utilization'; 'Unbundling ancillaries is core to the LCC model'; 'Legacy carriers launched LCC subsidiaries to compete.'

Load factor

Utilization metric defined as revenue passengers carried divided by seats offered (or RPK/ASK), indicating how full flights are.

'System load factor reached 85%'; 'Higher load factor does not guarantee profit if yields fall'; 'RM raised fares to lift yield at a stable load factor.'

MCT (Minimum Connection Time)

Published minimum time needed for a viable connection at an airport, varying by airline, terminal, and domestic/international pairing.

'Domestic-to-international MCT is 75 minutes here'; 'Schedule banks were built around the MCT'; 'Below-MCT misconnections require reprotection.'

MRO (Maintenance, Repair, and Overhaul)

Maintenance activities from line checks to heavy checks, either in-house or outsourced to third-party MRO providers.

'We insourced heavy MRO to control costs'; 'The MRO hangar focuses on C-checks'; 'MRO slot availability is tight this summer.'

MTOW (Maximum Takeoff Weight)

Certified maximum weight at which an aircraft is allowed to commence takeoff, constrained by performance, structural, and regulatory limits.

'High temperatures and short runway limited MTOW'; 'Charges are higher for aircraft with greater MTOW'; 'We offloaded payload to meet MTOW with full fuel.'

NOC/OCC (Network/Operations Control Center)

Central hub that manages day-of-operations decisions including disruptions, tail swaps, crew legality, and recovery plans.

'The OCC coordinated a system recovery after the storm'; 'Tail swaps were executed to protect long-hauls'; 'The NOC dashboard shows fleet status in real time.'

NOTAM (Notice to Air Missions)

Official notification of time-sensitive flight information such as outages, hazards, or procedure changes; pilots and dispatchers must review before flight.

'A NOTAM closed the ILS for maintenance'; 'Brief all runway closure NOTAMs during preflight'; 'Reforms aim to reduce NOTAM clutter and improve readability.'

O&D (Origin and Destination)

The true start and end points of a passenger’s journey, used to analyze demand, price discrimination, and network flows across hubs.

'O&D demand is strong in our local market'; 'RM protects high-yield O&D over low-yield connections'; 'Hub banks are timed to build O&D flows.'

OTP (On-time performance)

Punctuality metric, commonly measured as arrival within 15 minutes of schedule; tracked by DOT and industry sources.

'OTP dipped due to weather and ATC delays'; 'Stations are incentivized on D0 and A14 OTP'; 'Padding block times helped OTP but increased costs.'

Overbooking (Oversales)

Selling more seats than physical capacity to offset expected no-shows using forecast models and compensation policies for denied boarding.

'We oversold by 3 seats based on no-show rates'; 'Voluntary denied boarding cleared the oversell'; 'Rules cap compensation for involuntary bumps.'

PAX (Passengers)

Common shorthand for passengers; used in operations, weight and balance, and reporting.

'PAX count today is 162'; 'Misconnected PAX increased during the storm'; 'Standard PAX weights are applied for balance calculations.'

Payload

Weight available for revenue items (passengers, baggage, cargo) after accounting for aircraft empty weight and fuel; central to range–payload trade-offs.

'Hot-and-high conditions reduced allowable payload'; 'We prioritized bags over cargo to protect payload'; 'Range constraints forced a tech stop to carry full payload.'

PBN (Performance-Based Navigation)

Framework that specifies navigation performance requirements (accuracy, integrity) enabling RNAV and RNP routes and procedures, increasing capacity and efficiency.

'PBN airspace redesign cut track miles and emissions'; 'RNP AR approaches are part of PBN'; 'PBN deployment is a core element of NextGen and SESAR.'