Introduction
The airline industry uses specialized terminology covering operations, ticketing, aircraft, customer service, and industry regulations. Understanding this language is essential for aviation professionals, frequent travelers, and those interested in the aviation industry. This comprehensive cheatsheet provides a structured reference to airline terminology across multiple domains, from passenger-facing terms to technical operational language used by airline staff and industry insiders.
Ticketing & Fare Terminology
Fare Types & Classes
| Term | Definition |
|---|---|
| Economy/Coach Class | Standard cabin class offering basic amenities |
| Premium Economy | Enhanced economy class with added amenities and comfort |
| Business Class | Premium cabin with enhanced service, meals, and seating |
| First Class | Highest level of service offering maximum comfort and amenities |
| Basic Economy | Restricted economy fare with limited flexibility and amenities |
| Cabin Class | Designation of service level and seating section (e.g., economy, business) |
| Fare Basis Code | Alphanumeric code identifying fare type, restrictions, and routing |
| Published Fare | Standard fare available to the general public |
| Private Fare | Negotiated fare available to specific groups or through certain agencies |
| Consolidated Fare | Bulk fares purchased by consolidators and often sold below published rates |
Booking & Ticketing Terms
| Term | Definition |
|---|---|
| PNR | Passenger Name Record; booking reference code |
| GDS | Global Distribution System; reservation network (e.g., Sabre, Amadeus) |
| Open Ticket | Ticket valid for travel but without confirmed dates |
| Non-Refundable | Ticket that cannot be refunded for cash if canceled |
| Refundable | Ticket eligible for refund if unused or canceled |
| Changeable | Ticket that allows date/time modifications (may include fees) |
| Reissue | Process of modifying an existing ticket |
| EMD | Electronic Miscellaneous Document; used for ancillary services |
| Ticket Stock | Airlines’ inventory of ticket numbers |
| Conjunction Ticket | Multiple ticket numbers issued together for a single journey |
| Endorsement | Authorization to transfer a ticket to another airline |
| Exchange Rate Guarantee | Protection against currency fluctuations for international tickets |
Fare Rules & Restrictions
| Term | Definition |
|---|---|
| Advance Purchase | Required booking timeframe before departure (e.g., 14-day advance) |
| Minimum Stay | Shortest allowable period at destination before return |
| Maximum Stay | Longest allowable period before return journey must be completed |
| Blackout Dates | Specific dates when fare or awards cannot be used |
| Seasonality | Fare variations based on travel season (high, low, shoulder) |
| Stopover | Break in journey for more than 24 hours (international) or 4 hours (domestic) |
| Open-Jaw | Itinerary where outbound destination differs from return origin |
| Round-Trip | Journey to a destination and back to origin |
| One-Way | Journey from origin to destination without return |
| Circle Trip | Round-trip journey visiting multiple destinations |
| Fare Ladder | Hierarchy of fare levels within a cabin class |
Reservations & Check-In Terminology
Booking Status Codes
| Code | Meaning | Description |
|---|---|---|
| HK | Holding Confirmed | Confirmed reservation |
| HL | Holding Waitlist | On waitlist for flight |
| HX | Holding Cancelled | Reservation cancelled |
| NO | No Status | No action taken yet |
| RR | Reconfirmation Required | Passenger must reconfirm before flight |
| UC | Unable to Confirm | Unable to confirm requested booking |
| UN | Unable | Unable to accommodate request |
| SA | Space Available | Standby passenger accommodated if space available |
| NS | No Show | Passenger did not check in for flight |
Reservation Terms
| Term | Definition |
|---|---|
| Booking Class | Letter code designating specific fare type (Y, J, F, etc.) |
| Waitlist | Queue for passengers seeking seats on full flights |
| Standby | Passenger waiting for possible seat assignment |
| Upgrade | Moving to a higher cabin class |
| Downgrade | Moving to a lower cabin class |
| Segment | Portion of journey between takeoff and landing |
| Layover | Short stop between flights (typically under 24 hours) |
| Codeshare | Flight marketed by one airline but operated by another |
| Interline | Agreement allowing passengers to transfer between airlines |
| Block Space | Seats pre-purchased by a tour operator or company |
| Group Booking | Reservation for multiple passengers traveling together |
| Allocation | Reserved inventory of seats for specific distribution channels |
Check-In & Boarding
| Term | Definition |
|---|---|
| OLCI | Online Check-In; web-based process to obtain boarding pass |
| CUSS | Common Use Self-Service; shared kiosks for check-in |
| CUTE | Common Use Terminal Equipment; shared airline computer equipment |
| Boarding Pass | Document authorizing passenger to board aircraft |
| Gate | Designated area where passengers board aircraft |
| Boarding Sequence | Order in which passengers are allowed to board |
| Zone Boarding | Boarding by designated zones to control passenger flow |
| Pre-Boarding | Early boarding for passengers needing assistance |
| General Boarding | Main boarding phase for most passengers |
| Final Call | Last announcement before gate closure |
| Gate Lice | Informal term for passengers who crowd gate before their boarding group |
| FIDS | Flight Information Display System; screens showing flight status |
Airport & Aircraft Terminology
Aircraft Parts & Configurations
| Term | Definition |
|---|---|
| Fuselage | Main body of aircraft |
| Empennage | Tail section including vertical and horizontal stabilizers |
| Winglet | Upturned wing tips designed to reduce drag |
| Galley | Aircraft kitchen area |
| Flight Deck | Cockpit area where pilots operate aircraft |
| Bulkhead | Dividing wall within aircraft cabin |
| Exit Row | Seating row adjacent to emergency exit |
| Pitch | Distance between seats (legroom measurement) |
| Width | Seat width measurement |
| Lie-Flat | Seats that recline to horizontal sleeping position |
| Middle Seat | Less desirable seat between window and aisle |
| Bassinet Seat | Seat with attachments for infant bassinet |
Aircraft Types & Categories
| Term | Definition |
|---|---|
| Widebody | Large aircraft with two aisles (e.g., Boeing 777, Airbus A350) |
| Narrowbody | Smaller aircraft with single aisle (e.g., Boeing 737, Airbus A320) |
| Regional Jet | Smaller capacity jet for shorter routes (e.g., Embraer E-Jets) |
| Turboprop | Propeller aircraft powered by turbine engines (e.g., ATR, Q400) |
| ETOPS | Extended Operations; certification for long overwater flights |
| Equipment | Airline term for aircraft type |
| Equipment Swap | Change of aircraft type from scheduled equipment |
| Tail Number | Registration identifier painted on aircraft |
| Fleet | Collection of aircraft operated by an airline |
| Next-Gen | Newer generation aircraft with advanced technology |
Airport Facilities & Areas
| Term | Definition |
|---|---|
| Airside | Area beyond security checkpoints |
| Landside | Public access areas before security |
| Terminal | Building where passengers process and board flights |
| Concourse/Pier | Section of terminal containing gates |
| Jetway/Jet Bridge | Enclosed walkway connecting terminal to aircraft |
| Apron/Tarmac | Paved area where aircraft park |
| Taxiway | Path between runway and terminal |
| Runway | Surface where aircraft take off and land |
| FIS | Federal Inspection Services; customs and immigration |
| Baggage Claim | Area where checked luggage is returned to passengers |
| Lounge | Premium waiting area for eligible passengers |
| Priority Lane | Expedited security or check-in for premium passengers |
Airline Operations Terminology
Flight Scheduling & Operations
| Term | Definition |
|---|---|
| Block Time | Total time from gate departure to gate arrival |
| Flight Time | Time from takeoff to landing |
| Turnaround Time | Time needed between arrival and departure to service aircraft |
| Hub | Major airport serving as transfer point in airline network |
| Spoke | Destination connected to a hub |
| Point-to-Point | Direct flights between cities without focusing on hub connections |
| Red-Eye | Overnight flight departing late evening and arriving early morning |
| Rotation | Sequence of flights assigned to specific aircraft |
| Utilization | Measure of aircraft productive flying time |
| Slot | Authorized time for takeoff or landing at capacity-controlled airport |
| Frequency | Number of flights on a route in a given time period |
| Load Factor | Percentage of available seats occupied by passengers |
Operational Status Terms
| Term | Definition |
|---|---|
| On-Time Performance | Measurement of flights departing/arriving within 15 minutes of schedule |
| Delay | Flight operating later than scheduled time |
| Delay Codes | Standardized codes identifying delay causes |
| Cancellation | Flight that will not operate as scheduled |
| Diversion | Flight landing at airport other than scheduled destination |
| Ground Stop | Temporary halt to departures to specific destination |
| Ground Delay Program | FAA program managing departure times during congestion |
| ATC Delay | Delay caused by air traffic control restrictions |
| Weather Delay | Delay caused by adverse weather conditions |
| Mechanical Delay | Delay due to aircraft technical issues |
| Crew Delay | Delay due to crew availability or duty time limitations |
| Originating Delay | Initial delay in aircraft’s daily schedule |
Flight Crew & Staff
| Term | Definition |
|---|---|
| Pilot in Command (PIC) | Captain; primary person responsible for aircraft |
| First Officer | Co-pilot; second in command |
| Flight Attendant | Cabin crew member responsible for passenger safety and service |
| Purser/Chief Flight Attendant | Lead cabin crew member |
| Deadhead | Crew member traveling as passenger for positioning |
| Duty Time | Total time crew member is on duty (including pre/post flight) |
| Flight Time Limitations | Regulatory limits on crew flying hours |
| Rest Requirements | Mandatory rest periods between duty assignments |
| Crew Base | Airport where crew members begin and end duty periods |
| Check Airman | Pilot who evaluates other pilots’ performance |
| Jump Seat | Extra seat in cockpit or cabin for crew use |
| Crew Pairing | Series of flights worked by crew in duty period |
Passenger Experience Terminology
Loyalty Programs & Status
| Term | Definition |
|---|---|
| Frequent Flyer Program | Loyalty program offering benefits for repeat customers |
| Elite Status | Tiered recognition levels within loyalty program |
| Elite Qualifying Miles (EQM) | Miles counting toward status qualification |
| Elite Qualifying Dollars (EQD) | Spending counting toward status qualification |
| Elite Qualifying Segments (EQS) | Flight segments counting toward status qualification |
| Award Chart | Table showing miles required for free flights |
| Redemption | Using miles/points for flights or upgrades |
| Partner Airline | Airline where miles can be earned/redeemed through alliance |
| Earning Rate | Miles earned per dollar spent or distance flown |
| Status Match | Recognition of status from competing airline program |
| Status Challenge | Opportunity to earn status through accelerated qualification |
| Mileage Run | Trip taken primarily to earn miles or status credits |
Passenger Services
| Term | Definition |
|---|---|
| Special Meal | Custom meal meeting dietary, religious, or medical needs |
| Unaccompanied Minor (UM) | Child traveling without adult supervision |
| WCHR | Wheelchair required to/from gate (passenger can climb stairs) |
| WCHS | Wheelchair required to/from aircraft (cannot climb stairs) |
| WCHC | Wheelchair required to/from seat (immobile) |
| MEDA | Passenger requiring medical clearance to fly |
| PETC | Pet in cabin |
| AVIH | Pet in hold (cargo) |
| BIKE | Bicycle as baggage |
| GOLF | Golf equipment as baggage |
| SPEQ | Special equipment (oversized/sporting) |
| Meet and Assist | Service helping passengers navigate airport |
Baggage Terminology
| Term | Definition |
|---|---|
| Checked Baggage | Luggage transported in aircraft cargo hold |
| Carry-On Baggage | Luggage brought into passenger cabin |
| Personal Item | Smaller item allowed in addition to carry-on (purse, laptop bag) |
| Maximum Dimensions | Size limits for baggage |
| Weight Allowance | Maximum permitted baggage weight |
| Excess Baggage | Luggage exceeding weight or piece allowance |
| Overweight Baggage | Bags exceeding standard weight limit |
| Oversized Baggage | Bags exceeding standard dimension limits |
| Baggage Tag | Identifier attached to checked luggage |
| Delayed Baggage | Luggage that doesn’t arrive with passenger |
| Mishandled Baggage | Luggage that is lost, delayed, or damaged |
| Baggage Claim Tag | Receipt given to passenger for checked items |
Industry & Business Terminology
Airline Alliances & Partnerships
| Term | Definition |
|---|---|
| Alliance | Formal cooperation between multiple airlines (e.g., Star Alliance) |
| Oneworld | Alliance including American Airlines, British Airways, Cathay Pacific, etc. |
| SkyTeam | Alliance including Delta, Air France-KLM, Korean Air, etc. |
| Star Alliance | Alliance including United, Lufthansa, Singapore Airlines, etc. |
| Joint Venture | Deep partnership with shared revenue on specific routes |
| Bilateral Agreement | Treaty between countries governing air service rights |
| Interline Agreement | Contract allowing airlines to handle each other’s passengers |
| Special Prorate Agreement | Financial arrangement for sharing interline revenue |
| Fifth Freedom | Right to carry passengers between two foreign countries |
| Cabotage | Domestic air service by foreign carrier (usually prohibited) |
| Wet Lease | Aircraft leased with crew and maintenance included |
| Dry Lease | Aircraft leased without crew or maintenance |
Business & Financial Terms
| Term | Definition |
|---|---|
| Revenue Passenger Mile (RPM) | One paying passenger flown one mile |
| Available Seat Mile (ASM) | One seat flown one mile |
| Cost Per Available Seat Mile (CASM) | Operating cost to fly one seat one mile |
| Revenue Per Available Seat Mile (RASM) | Revenue generated per available seat mile |
| Yield | Average fare paid per mile per passenger |
| Ancillary Revenue | Non-ticket revenue (baggage fees, seat selection, etc.) |
| IROP | Irregular Operation; disruption to normal schedule |
| Load Factor | Percentage of seats filled with passengers |
| Spill | Potential passengers unable to book due to capacity constraints |
| Stimulation | Increased demand due to lower fares |
| Dilution | Reduced average fare due to discounting |
| Leakage | Passengers using alternative airports or carriers |
Industry Organizations & Regulations
| Term | Definition |
|---|---|
| IATA | International Air Transport Association |
| ICAO | International Civil Aviation Organization |
| FAA | Federal Aviation Administration (US) |
| EASA | European Union Aviation Safety Agency |
| CAA | Civil Aviation Authority (UK and others) |
| DOT | Department of Transportation (US) |
| TSA | Transportation Security Administration (US) |
| CAB | Civil Aeronautics Board (historical US regulatory body) |
| Deregulation | Removal of government controls over routes, fares, etc. |
| Open Skies | Treaties liberalizing international air service |
| Freedoms of the Air | Set of commercial aviation rights for international services |
| Passenger Rights | Regulations governing compensation for delays/cancellations |
Air Traffic & Navigation Terminology
Air Traffic Control
| Term | Definition |
|---|---|
| ATC | Air Traffic Control |
| Clearance | Permission for specific aircraft movement |
| IFR | Instrument Flight Rules; flying by reference to instruments |
| VFR | Visual Flight Rules; flying by visual references |
| Ground Control | ATC position handling aircraft on taxiways |
| Tower | ATC position handling takeoffs and landings |
| Approach | ATC position handling arriving aircraft |
| Departure | ATC position handling departing aircraft |
| Center | ATC facility handling en route traffic |
| TRACON | Terminal Radar Approach Control; handles approach/departure |
| Flow Control | Management of traffic volume to match capacity |
| Holding Pattern | Oval flight path for delaying aircraft |
Navigation & Flight Planning
| Term | Definition |
|---|---|
| Waypoint | Specific geographic position used for navigation |
| SID | Standard Instrument Departure; standardized departure route |
| STAR | Standard Terminal Arrival Route; standardized arrival procedure |
| Approach Procedure | Path and maneuvers for landing at airport |
| Flight Plan | Filed route and details for ATC purposes |
| Great Circle Route | Shortest path between two points on Earth’s surface |
| Mach Number | Aircraft speed relative to speed of sound |
| Flight Level | Altitude expressed in hundreds of feet (e.g., FL350 = 35,000 ft) |
| TOD | Top of Descent; point where aircraft begins descent |
| TOC | Top of Climb; point where aircraft reaches cruise altitude |
| ETOPS | Extended Operations; certification for flights far from diversion airports |
| MEL | Minimum Equipment List; items that may be inoperative for flight |
Weather Terminology
| Term | Definition |
|---|---|
| METAR | Aviation routine weather report |
| TAF | Terminal Aerodrome Forecast |
| Crosswind | Wind component perpendicular to runway |
| Ceiling | Height of lowest cloud layer covering more than half the sky |
| Visibility | Distance at which objects can be identified |
| Turbulence | Irregular air motion causing aircraft to shake |
| Wind Shear | Sudden change in wind direction or speed |
| Microburst | Intense small-scale downdraft |
| Icing | Ice formation on aircraft surfaces |
| Thunderstorm | Storm with lightning and thunder |
| Clear Air Turbulence | Turbulence in clear sky without visual indicators |
| Jet Stream | High-altitude, high-speed wind current |
Common Abbreviations & Acronyms
Flight & Service Abbreviations
| Abbreviation | Meaning |
|---|---|
| ACARS | Aircraft Communications Addressing and Reporting System |
| APIS | Advance Passenger Information System |
| BOB | Buy On Board (food/beverage for purchase) |
| CTOT | Calculated Take-Off Time |
| DGR | Dangerous Goods Regulations |
| ETA | Estimated Time of Arrival |
| ETD | Estimated Time of Departure |
| FLIFO | Flight Information |
| IFE | In-Flight Entertainment |
| LMC | Last Minute Change |
| MCT | Minimum Connection Time |
| OAG | Official Airline Guide |
| PAX | Passengers |
| SARS | Seat Assignment and Reservation System |
| SSIM | Standard Schedules Information Manual |
| VDB | Voluntary Denied Boarding |
| IDB | Involuntary Denied Boarding |
| VGML | Vegetarian Meal |
| VLML | Lacto-Ovo Vegetarian Meal |
| DBML | Diabetic Meal |
| FPML | Fruit Platter Meal |
| KSML | Kosher Meal |
| MOML | Muslim Meal |
Technical & Operational Abbreviations
| Abbreviation | Meaning |
|---|---|
| APU | Auxiliary Power Unit |
| ATA | Actual Time of Arrival |
| ATD | Actual Time of Departure |
| BITE | Built-In Test Equipment |
| CDM | Collaborative Decision Making |
| EDCT | Expected Departure Clearance Time |
| EFC | Expected Further Clearance |
| EFOB | Expected Fuel On Board |
| ELT | Emergency Locator Transmitter |
| HOTAC | Hotel Accommodation (for crew) |
| LOPA | Layout of Passenger Accommodations |
| MEA | Minimum Enroute Altitude |
| MTOW | Maximum Take-Off Weight |
| OFP | Operational Flight Plan |
| RVSM | Reduced Vertical Separation Minimum |
| SOC | System Operations Control |
| NOTAM | Notice to Airmen |
| ZFW | Zero Fuel Weight |
| TOW | Take-Off Weight |
| T/O | Take-Off |
| ACMI | Aircraft, Crew, Maintenance, Insurance (lease type) |
| AOG | Aircraft On Ground (maintenance status) |
Resources for Further Learning
Industry Publications & Websites
- Air Transport World: Professional airline industry magazine
- Aviation Week & Space Technology: Aerospace industry publication
- FlightGlobal: News and analysis for aviation industry
- CAPA Centre for Aviation: Industry analysis and data
- Simple Flying: Commercial aviation news and features
- The Points Guy: Frequent flyer and travel resource
- AirlineGeeks: Aviation news and information
- Airways Magazine: Commercial aviation publication
Professional Organizations
- IATA: International Air Transport Association
- ICAO: International Civil Aviation Organization
- ACI: Airports Council International
- RAA: Regional Airline Association
- A4A: Airlines for America (formerly Air Transport Association)
- ALPA: Air Line Pilots Association
- AFA: Association of Flight Attendants
- NBAA: National Business Aviation Association
Books & Reference Materials
- “From the Flight Deck: Plane Talk and Sky Science” by Doug Morris
- “Practical Aviation & Aerospace Law” by J. Scott Hamilton
- “Straight and Level: Practical Airline Economics” by Stephen Holloway
- “Hard Landing: The Epic Contest for Power and Profits That Plunged the Airlines into Chaos” by Thomas Petzinger Jr.
- “The Global Airline Industry” by Peter Belobaba, Amedeo Odoni, and Cynthia Barnhart
- “Flying the Line” by George E. Hopkins (airline pilot history)
Quick Tips for Air Travelers
- When discussing flight numbers, always include the airline code (e.g., DL123 instead of just “flight 123”)
- Learn key airport codes for your frequent destinations (e.g., LAX for Los Angeles)
- Understand fare basis codes on your ticket to know your fare restrictions
- Know your frequent flyer program earning and redemption rules
- Familiarize yourself with your airline’s baggage policies before packing
- Note minimum connection times at major airports you transit
- Learn boarding group terminology for your preferred airlines
- Understand codeshare relationships when booking partner flights
- Keep track of schedule change policies for your booked flights
- Know the differences between “direct” (one flight number with stops) and “non-stop” flights