We are presenting a comprehensive glossary of commercial aviation terms. We are hopeful that it will help readers capture more efficiently some of the key aspects of our analysis. As well we are confident that it can also help navigate more efficiently the numerous financial documents, news articles, research papers …etc that are available to the public. We are giving special attention to global airlines by incorporating terms extracted from Lufthansa and Air France-KLM glossaries. Although most of the terms are clearly referring to the US Bureau Of Transportation Statistics which we believe provide by far the most relevant source of data in order to conduct insightful commercial aviation data analysis.

Actual Arrival Times (BTS)

Gate arrival time is the instance when the pilot sets the aircraft parking brake after arriving at the airport gate or passenger unloading area.  If the parking brake is not set, record the time for the opening of the passenger door.  Also, carriers using a Docking Guidance System (DGS) may record the official gate-arrival time when the aircraft is stopped at the appropriate parking mark.

Actual Departure Times (BTS)

Gate departure time is the instance when the pilot releases the aircraft parking brake after passengers have loaded and aircraft doors have been closed. In cases where the flight returned to the departure gate before wheels-off time and departed a second time, report the last gate departure time before wheels-off time.  In cases of an air return, report the last gate departure time before the gate return.  If passengers were boarded without the parking brake being set, record the time that the passenger door was closed.  Also, carriers using a Docking Guidance System may record the official gate-departure time based on aircraft movement.  For example, one DGS records gate departure time when the aircraft moves more than 1 meter from the appropriate parking mark within 15 seconds.  Fifteen seconds is then subtracted from the recorded time to obtain the appropriate out time.

Air (BTS)

Air service for shipments that typically weigh more than 100 pounds using commercial or private aircraft. Includes air freight and air express.

Air Freight (BTS)

Property, other than express and passenger baggage transported by air.

Air Taxi (BTS)

A classification of air carriers established by which operate small aircraft, and do not hold a certificate of public convenience and necessity.

Air Time (BTS)

The airborne hours of aircraft computed from the moment an aircraft leaves the ground until it touches the ground at the end of a flight stage.

Air Traffic Liabilities (BTS)

The value of transportation sold but not used or refunded; i.e., (1) liabilities to passengers, or (2) liabilities to others. These include payables to other airlines for portions of inter-airline passenger trips – amounts the ticketing carrier owes the performing carrier. Also included are amounts the ticketing carrier owes to passengers prior to flights – which remain unearned revenue until air transportation is provided.

Air Trip (BTS)

Any trip in which the type of transportation used to cover most of the miles on that trip was either by commercial airplane or a personal or corporate airplane.

Aircraft And Traffic Servicing Expenses (BTS)

Compensation of ground personnel, in-flight expenses for handling and protecting all non-passenger traffic including passenger baggage, and other expenses incurred on the ground to (1) protect and control the in-flight movement of the aircraft, (2) schedule and prepare aircraft operational crew for flight assignment, (3) handle and service aircraft while in line operation, and (4) service and handle traffic on the ground after issuance of documents establishing the air carrier’s responsibility to provide air transportation.

Aircraft Configuration (BTS)

The type of payload an aircraft was designed to carry: passenger, cargo, or both.

Aircraft Days Assigned (BTS)

The number of days that aircraft owned or acquired through rental or lease (but not inter-change) are in the possession of the reporting air carrier and are available for service on the reporting carrier’s routes plus the number of days such aircraft are in service on routes of others under interchange agreements. Includes days in overhaul, or temporarily out of service due to schedule cancellations. Excludes days that newly acquired aircraft are on hand but not available or formally withdrawn from air transport service.

Aircraft Hours (BTS)

The airborne hours of aircraft computed from the moment an aircraft leaves the ground until it touches the ground at the end of a flight stage.

Aircraft Operating Expenses (BTS)

Expenses incurred directly in the in-flight operation of aircraft.

Airline ID (BTS)

An identification number assigned by US DOT to identify a unique airline (carrier). A unique airline (carrier) is defined as one holding and reporting under the same DOT certificate regardless of its Code, Name, or holding company/corporation.

Airport Code (BTS)

A three character alpha-numeric code issued by the U.S. Department of Transportation which is the official designation of the airport.

Arrival Delay (BTS)

Arrival delay equals the difference of the actual arrival time minus the scheduled arrival time. A flight is considered on-time when it arrives less than 15 minutes after its published arrival time.


Available seat kilometres (ASK) measures an airline’s passenger carrying capacity. It is the seating capacity multiplied by the number of kilometres flown. It is used to compare one airline’s capacity with another.

Assets (BTS)

Current Assets include cash, accounts receivable, notes receivable. Long-term assets include net carrier operating property.

Available Seat Miles (BTS)

The aircraft miles flown in each inter-airport segment multiplied by the number of seats available for revenue passenger use on that segment.

Available Seats (BTS)

The number of seats available for revenue passenger use on a flight segment.

Average Miles Per Shipment (BTS)

The 1993 CFS excluded shipments of STCC 27, Printed Matter, from calculation of average miles per shipment. This was done after determining that respondents in the 1993 CFS shipping newspapers, magazines, catalogs, etc., had used widely varying definitions of the term shipment. In the 1997 CFS, numerous efforts were made during data collection and editing to produce consistent results from establishments shipping SCTG 29, Printed Products. As a result, average miles per shipment for printed products is included in calculations for the 1997 CFS.


Computer Reservation System. CRS provide information on airline schedules, fares and seat availability to travel agencies and allow agents to book seats and issue tickets.


Cabotage is the transport of goods or passengers between two points in the same country by an airline belonging to another county.

Cash flow (Lufthansa)

Measure of a company’s financial and earnings potential. It is calculated as the difference between the inflow and outflow of cash and cash equivalents generated from ongoing business activities during the financial year (see “consolidated cash flow statement” ).

Cash value added – CVA (Lufthansa)

Parameter for measuring performance of value creation. When the cash flow generated in a period (EBITDAplus) is greater than the minimum cash flow required to cover the cost of capital, the CVA is positive and value is created (see chapter “Value-based management” ).

Cancelled Flight (BTS)

A flight that was listed in a carrier’s computer reservation system during the seven calendar days prior to scheduled departure but was not operated.

Carrier Code (BTS)

Code assigned by IATA and commonly used to identify a carrier. As the same code may have been assigned to different carriers over time, the code is not always unique.


Route Profit Centre: The Air France network is divided into six different geographic sectors: France, Europe, Africa & Middle East, Americas, Asia and Caribbean & Indian Ocean.

Certificate Of Public Convenience And Necessity (BTS)

A certificate issued to an air carrier under 49 U.S.C. 41102, by the Department of Transportation authorizing the carrier to engage in air transportation.

Certificated Air Carrier (BTS)

An air carrier holding a Certificate of Public Convenience and Necessity issued by DOT to conduct scheduled services interstate. Nonscheduled or charter operations may also be conducted by these carriers. (same as Certified Air Carrier)

Certified Air Carrier (BTS)

An air carrier holding a Certificate of Public Convenience and Necessity issued by DOT to conduct scheduled services interstate. Nonscheduled or charter operations may also be conducted by these carriers. (same as Certificated Air Carrier)

Charter Flight (BTS)

A commercial passenger vehicle trip not scheduled, but specially arranged. The charter contract normally commits the carrier to furnish the agreed to transportation service at a specified time between designated locations.

Chief purser (AF-KLM)

Supervises the cabin crew on board wide-bodies. He or she is generally assisted by pursers.

Class of travel (AF-KLM)

Corresponds to a certain quality of services offered to the customer. This level of quality corresponds to a cabin class. Air France offers different classes of travel: Espace Première, Espace Affaires, Tempo Challenge, Tempo or Alizé.

Codeshare (BTS)

An arrangement whereby a marketing carrier’s code is used to identify a flight operated by another carrier. The marketing carrier may make reservations and issue tickets for the operating carrier’s flights.


In accordance with a code sharing agreement, two partner airlines offer services on the same aircraft, each with their own brand, their own IATA code and their own flight number.

Commuter Air Carrier (BTS)

An air taxi that provides scheduled passenger service between two points at least 5 days a week.

Completed Departures (BTS)

Takeoffs made at an airport. (same as Departures Performed)

Coordinated airport (AF-KLM)

These are airports where in order to operate the airport is coordinated, and each airline has been allocated a slot by an independent coordinator, according to previously established rules. In Europe all the major airports are coordinated.

Coupon (BTS)

A piece of paper or series of papers indicating the itinerary of a passenger. An airline ticket includes an auditor’s coupon, flight coupons, and a passenger receipt.

Departure Delay (BTS)

The difference between the scheduled departure time and the actual departure time from the origin airport gate

Departures Performed (BTS)

Takeoffs made at an airport. (same as Completed Departures)

Departures Scheduled (BTS)

Takeoffs scheduled at an airport, as set forth in published schedules.

Destination (BTS)
For travel period trips, the destination is the farthest point of travel from the point of origin of a trip of 75 miles or more one-way. For travel day trips, the destination is the point at which there is a break in travel.

Destination Of Trip (BTS)

The place reported by a respondent as the destination of the trip. If more than one place is visited on the same trip, the place which is the farthest point from the origin is considered the destination of the trip.

Distance Shipped (BTS)

The distance between origin and destination for a shipment. For the distance shipped intervals table, the distance is calculated based on the great circle distance between the origin and destination ZIP Code centroids. All other distance-related data (i.e., ton-miles and average miles per shipment) are based on the mileage calculations produced by Oak Ridge National Laboratories.

Diverted Flight (BTS)

A flight that is required to land at a destination other than the original scheduled destination for reasons beyond the control of the pilot/company.

Domestic Operations (BTS)

All air carrier operations having destinations within the 50 United States, the District of Columbia, the Commonwealth of Puerto Rico, and the U.S. Virgin Islands.

Duration Of Trip (BTS)

Number of nights spent away from home on a trip and includes nights spent at the destination, nights spent en route and nights spent on side trips. It is possible for a trip not to involve an overnight stay from home; a traveler could take a trip of 100 miles or more and return on the same day.


French Civil Aviation Authority. Reports to the French ministry of transport, the DGAC is in charge of air safety in France.

Dow Jones Sustainability Index

The Dow Jones Sustainability World (DJSI World) index comprises, among the 2,500 biggest companies in the Dow Jones index, 10% of the most economically, environmental and socially efficient companies.


The EASA is a European Union body responsible for regulations concerning civil aviation in all EU countries. The Agency also provides expertise when drafting European Union legislation.

EBITDA (Lufthansa)

Financial indicator denoting earnings before interest, taxes, depreciation and amortisation. Depreciation relates to items of property, plant and equipment and amortisation to intangible assets – both terms apply equally to non-current and current assets. The figure also includes impairment losses on equity investments accounted for under the equity method and on assets held for sale.


European civil aviation conference Represents the European civil aviation regulatory authorities of the

Elapsed Time (BTS)

The time computed from gate departure time to gate arrival time.

Employed (BTS)

A person is considered employed if there is a definite arrangement for regular full-time or part-time work for pay every week or every month. A formal, definite arrangement with one or more employers to work a specified number of hours a week, or days a month, but on an irregular schedule during the work month is also considered employment. A person who is on call to work whenever there is a need for his (her) services is not considered employed.

Equipment Class (BTS)

A three character alpha-numeric code designated by the Official Airline Guide (published by the U.S. Department of Transportation) which specifies the type of aircraft being used for the flight from the point of origin.

Equity method (Lufthansa)

Accounting method for measuring income derived from a company’s investments in associated companies and joint ventures. Under this method, investment income equals a share of net income proportional to the size of the equity investment.


Extended-range Twin-engine Operations

Flight Equipment (BTS)

All types of property and equipment used in the in-flight operation of aircraft.

Flight Number (BTS)

A one to four character alpha-numeric code for a particular flight

Flying Operations Expenses (BTS)

Expenses incurred directly in the in-flight operation of aircraft and expenses related to the holding of aircraft and aircraft operational personnel in readiness for assignment for an in-flight status.

Form 41 Financial Statistics (BTS)

The statistics collected on the financial forms submitted monthly, quarterly, semiannually, and annually to BTS by each large certificated air carrier subject to the Federal Aviation Act of 1958. The four classes of financial and operating statistics collected on individual schedules of the Form 41 Report are grouped as follows: (A) Certification, (B) Balance Sheet Elements, (P) Profit and Loss Elements, and (T) Traffic and Capacity Elements.

Form 41 Report (BTS)

The schedule of forms submitted monthly, quarterly, semiannually, and annually to BTS by each large certificated air carrier subject to the Federal Aviation Act of 1958.

Form M (BTS)

Class I and II motor carriers are required to annually submit financial, operating, and employment data to Bureau of Transportation Statistics using Form M. Also known as the Motor Carrier Annual Report Form M.

Form QFR (BTS)

Class I motor carriers are required to submit financial and operating data to Bureau of Transportation Statistics each quarter using Form QFR. Also known as the Motor Carrier Quarterly Report Form QFR.


Inflight meals are stored and prepared in the galley. Besides being to keep food and beverages carts, there is also storage for chinaware and cuttlery as well as ovens and refrigerators.


Global Distribution System:
A computerized information and reservations system, enabling travel agents to visualize the inventory available for various products supplied by professionals in the tourism industry (airlines, hotel chains, car hire, etc.) In 1987, Air France, together with Iberia, Luftahansa and SAS set up Amadeus.


A go-around or balked landing is used to describe a manoeuvre whereby the pilot, for whatever reason, decides to abort the landing. The go-around procedure may also be dictated by the control tower because of weather conditions or because the runway is not clear.


Ground proximity warning system: decision-making aid used to alert pilots of an obstacle

Great Circle Distance (BTS)

The shortest distance between two points on the earth’s surface.


Hedging Policy: Financial mechanism used by Air France KLM and other airlines to minimize the effects of hikes in the cost of  fuel. It involves buying a certain quantity of jetfuel at a certain date at a prearranged price. Two other kinds of financial products, options and swaps, are used in this type of financial strategy.

Hold baggage (AF-KLM)

Baggage carried in the aircraft hold, at the airline’s responsibility. Hold baggage is checked and labelled. Air France is developing the “intelligent” baggage tag using RFID technology allowing to track the bag’s movements.

Hub (AF-KLM)

An airline’s central airport where arrivals and departures are scheduled to coincide so that connecting times are reduced. At  Paris-Charles de Gaulle passengers arrive in six connecting time bands throughout the day. Usually  part of a ‘hub and spoke’ strategy, passengers and goods from surrounding airports (spokes) are transferred via ‘feeder flights’ to their joint
final destination or vice versa.


International Air Transport Association Set up in 1945 in Havanna, Cuba, IATA represents most of the world’s airlines. It’s mission is to encourage the development of air transport through the unification and coordination of  international standards and regulations.

IATA airport code

International coding system defined by the IATA association, comprising a 3-letter code.

IATA year

The fiscal calendar year adopted by many airlines, including Air France, which begins on 1 April and ends on 31 March of the following year, allowing carriers to monitor operations more easily on the basis of IATA “defined seasons” (winter and summer).


International Civil Aviation Organization: Set up at the Chicago Convention in 1944, it was designed to define the texts, standards and recommendations necessary to regulate civil aviation.  The headquarters are located in Montreal.


In Flight Entertainment: An electronic entertainment system provided for passengers including video, audio and telephony. In the most recent cabin fittings this is also interactive.


Instrument flight rules (IFR) are a set of regulations and procedures for flying aircraft whereby aircraft instruments provide navigation and obstacle clearance (together with instructions from the Air Traffic Control). See also VFR (visual flight rules).


International Financial Reporting Standards: Accounting standards used by listed companies in the European Union for their consolidated accounts. Adopted on 1 January 2005, it has made it easier for investors to compare the financial perforamance of European companies.


ILS (Instrument Landing System) is a radio system used for precision guidance when landing aircraft, particularly in bad visibility. This equipment significantly improves landing precision by combining lateral and vertical guidance.

Impairment (Lufthansa)

Losses recognized on the carrying amount of assets. Impairment charges are recognized when an asset’s “recoverable value” (the higher of fair value less costs to sell and value in use) is below its carrying amount. By contrast, depreciation or amortization is the systematic allocation of the depreciable amount of an asset over its useful life.

Inertial Navigation Unit

A computer that tells the aircraft where it is in relation to the Earth’s surface in three dimensions, with no external radio or satellite assistance.

In-Flight Time (BTS)

The total time an aircraft is in the air between an origin-destination airport pair, i.e. from wheels-off at the origin airport to wheels-down at the destination airport.


IOSA certification is obtained after a series of audits carried out within airlines. These audits are conducted by organizations accredited by IATA and are based on close to a thousand different aspects related to the safety of air operations, such as flight and ground operations, operational control and even maintenance. IOSA certification ensures that the airline’s safety procedures meet the highest standards of the international aviation industry. Air France has obtained IOSA certification.


The IPCC (Intergovernmental Panel on Climate Change) was created in 1988 by two UN bodies; the World Meteorological Organization (WMO) and  the United Nations Environment Programme (UNEP). The IPCC’s role is to provide decision-makers with objective information on climate change in a clear and methodical manner based on the latest scientific, technical and socio-economic literature. In 2007 the IPCC was awarded the Nobel Peace prize.

ISO 14001

International standard promoting the quality of environmental policies.  First published in 1996, ISO 14001 has become a strategic reference in terms of environmental management. The company which requests certification is audited by an accredited, international independent body. ISO 14001 is based on three requirements: • ensure compliance with environmental regulations; • prevent pollution; • constantly seek to improve environmental performance. Air France entrusted the Quality, Environment and Sustainable Development Division with the task of obtaining ISO 14001 Certification in October 2007. The target is to achieve certification by summer 2008.


Joint Aviation Authorities


A jetway or overhead walkway may be more or less at a slope and is used to connect an aircraft to the airport building.


Unit used to measure airspeed. I knot = 1.852 kilometers an hour or 1.1507 miles per hour

Kyoto Protocol

The purpose of the Kyoto Protocol is to combat climate change by reducing carbon dioxide emissions.  The Earth Summit in Rio in 1992 marked the awareness on an international scale of the risk of climate change.  The richest countries, for which a reduction in growth did not seem acceptable but which were responsible for most of the emissions, made a commitment to stabilize their emissions at 1990 levels by the year 2000.  The Kyoto Protocol of 1997 reflects this determination in terms of quantitative, legally- restrictive commitments. In the protocol, 39 industrialized countries including Europe, Russia, Japan and Australia which ratified the agreement In December 2007, will reduce their emissions of six greenhouse gases between 2008 and 2012 by 5.2% compared to the year 1990, in order to combat global warming. The targets differ from one country to another: Target for Europe: – 8% Target for France: 0% (given its nuclear power stations, France only needs to maintain the same level of emissions as in 1990).

Large Certificated Air Carrier (BTS)

An air carrier holding a certificate issued under 49 U.S.C.41102, as amended, that: (1) Operates aircraft designed to have a maximum passenger capacity of more than 60 seats or a maximum payload capacity of more than 18,000 pounds; or (2) conducts operations where one or both terminals of a flight stage are outside the 50 states of the United States, the District of Columbia, the Commonwealth of Puerto Rico and the U.S. Virgin Islands. (same as Large Certified U.S. Air Carriers)

Large Certified U.S. Air Carriers (BTS)

An air carrier holding a certificate issued under 49 U.S.C.41102, as amended, that: (1) Operates aircraft designed to have a maximum passenger capacity of more than 60 seats or a maximum payload capacity of more than 18,000 pounds; or (2) conducts operations where one or both terminals of a flight stage are outside the 50 states of the United States, the District of Columbia, the Commonwealth of Puerto Rico and the U.S. Virgin Islands. (same as Large Certificated Air Carrier)

Late Flight (BTS)

A flight arriving or departing 15 minutes or more after the scheduled time.


An agreement under which a property owner allows an operating carrier to use a means of transport during a specified period. There are two main types of lease: dry lease and wet lease.

Liabilities (BTS)

Current liabilities include accounts payable, notes payable, taxes payable, and current portion of long-term debt. Long-term liabilities include long-term debt.

Long haul

Long-haul flights usually last over five hours

Maintenance Expense (BTS)

All expenses, both direct and indirect, specifically identifiable with the repair and upkeep of property and equipment.

Market (Using DB1B Data) (BTS)

A Market in DB1B data is created by a trip break. Trip Breaks are points in the itinerary at which a passenger is assumed to have stopped for a reason other than changing planes. For example: an itinerary BOS-LAS-BOS would have two markets BOS-LAS and LAS-BOS. The trip break occurred at LAS.

Market (Using T100 Data) (BTS)

Market data are passenger, freight, and/or mail that enplane and deplane between two specific points, while the flight number remains the same. If the flight number changes a new market begins. For more details go to

Marketing Carrier (BTS)

An air carrier that issued a flight reservation or ticket under a code share agreement.

Medium haul (AF-KLM)

Medium-haul flights usually lasts less than five hours and for Air France generally refer to European flights.

Mile (BTS)

A statute mile (5,280 feet). All mileage computations are based on statute miles.


The Microwave Landing System (MLS) is an all-weather, precision landing system that will be fitted in the next few years to supplement the already operational Instrument Landing System (ILS).

Montreal Convention

An international convention designed to unify certain rules governing international air transport, signed in Montreal on 28 May 1999 and ratified on 28 June 2004 by EU countries. The Montreal Convention introduced the principle of carriers’ civil liability for victims of air disasters. With additional and more detailed provisions it will eventually replace the Warsaw Convention.

Multiple Modes (BTS)

Parcel, U.S. Postal Service or courier shipments or shipments for which two or more of the following modes of transportation were used: private truck, for-hire truck, rail, shallow draft vessel, deep draft vessel, or pipeline.


A nautical mile or sea mile is a unit of length, measuring 1,852 metres.

Non-Revenue Traffic (BTS)

Passengers and cargo transported by air for which no remuneration or token service charges are received by the air carrier. Airline employees, officers and directors, or other persons, except for ministers of religion, who are traveling under reduced rate transportation authorized by 49 U.S.C. 41511(a) and 14CFR part 223, as well as travel agents, cargo agents, and tour conductors traveling at reduced fares are also considered non-revenue traffic.

Non-Scheduled Service (BTS)

Revenue flights, such as charter flights, that are not operated in regular scheduled service.

Non-operating Income And Expense (BTS)

Interest income and expense, unusual foreign exchange gains or losses, and capital gains or losses in disposition of property and equipment.

Operating Carrier (BTS)

An air carrier engaged directly in the operation of aircraft in passenger air transportation.

Operating costs

Costs arising from normal operating conditions in a company.

Operating Expenditure (BTS)

Expenses from wages and salaries, operating supplies, insurance expenses, and other miscellaneous expenses.

Operating Expenses (BTS)

Expenses incurred in the performance of air transportation, based on overall operating revenues and overall operating expenses. Does not include non-operating income and expenses, nonrecurring items, or income tax

Operating noise

Actual noise perceived on the ground during aircraft maneouvre (departure and approach).

Operating Region (BTS)

One of six regions used to describe the region where an air carrier operates: International (Atlantic, Pacific, and Latin America), System (all regions covered by an air carrier), Domestic (U.S.), Atlantic, Pacific, Latin America. For those carriers with international flights, the operating region is determined by where its flights leave and enter the U.S.

Operating result (Lufthansa)

Measure of profitability denoting the operating result calculated as the result of operating activities, adjusted for book gains and losses, write-backs of provisions, exchange rate gains and losses on the measurement of non-current borrowing as of the reporting date and income and expenses relating to other periods

Operating Revenue (BTS)

Revenue from the transportation of property or passengers by motor carrier.

Operating Revenues (BTS)

Revenues from the performance of air transportation and related incidental services. Includes (1) transport revenue from the carriage of all classes of traffic in scheduled and nonscheduled services, and (2) non-transport revenues consisting of Federal subsidy (where applicable) and revenues for services related to air transportation.

Origin (BTS)

Starting point of a trip.

Other Transport-Related Revenue (BTS)

Revenues from services such as in-flight sales, rentals and sales or services, supplies and parts.


Airlines overbook flights to compensate for passengers who reschedule or opt not to fly (‘no-shows’).

Payload (BTS)

Equal to the certificated takeoff weight of an aircraft, less the empty weight, less all justifiable aircraft equipment, and less the operating load (consisting of minimum fuel load, oil, flight crew, steward’s supplies, etc).

Peak-period Trip (BTS)

Any travel day trip that began between 6:30 a.m. and 9:00 a.m. or from 3:30 p.m. to 6:00 p.m.

Person Miles of Travel (PMT) (BTS)

A measure of person travel. When one person travels one mile, one person mile of travel results. Where 2 or more persons travel together in the same vehicle, each person makes the same number of person miles as the vehicle miles. Therefore, four persons traveling 5 miles in the same vehicle, make 4 times 5 or 20 person miles.


Leg-room or distance between two seats.

Promotion And Sales Expenses (BTS)

Cost incurred in promoting the use of air transportation generally and creating a public preference for the services of particular air carriers. Includes the functions of selling, advertising, and publicity, space reservations, and developing tariffs and flight schedules for publication.


Percentage of flights which have left/arrived on time or within 15 minutes


Supervises the cabin crew (flight attendants) on a flight.

Passenger Mile (BTS)

One passenger transported one statute mile. Total passenger miles are computed by summation of the products of the aircraft miles flown on each inter-airport flight stage multiplied by the number of passengers carried on that flight stage.One passenger transported one statute mile. Total passenger miles are computed by summation of the products of the aircraft miles flown on each inter-airport flight stage multiplied by the number of passengers carried on that flight stage.


Atmospheric pressure (Q) at Field Elevation


Atmospheric Pressure (Q) at Nautical Height


Quick Return Flight: Code used in aviation to signify that an aircraft is returning to base due to a technical incident.

Ramp To Ramp Time (BTS)

The time computed from the moment an aircraft first moves under its own power for purposes of flight, until it comes to rest at the next point of landing.


Percentage of flights performed compared with scheduled flights

Reporting Carrier (BTS)

The carrier that submitted data to the Office of Airline Information for a given passenger segment.

Revenue (BTS)
Pertaining to activities for which remuneration is received by the carrier.

Revenue Passenger Mile (BTS)

One revenue passenger transported one mile in revenue service. Revenue passenger miles are computed by summation of the products of the revenue aircraft miles on each inter-airport segment multiplied by the number of revenue passengers carried on that segment.

Revenue Ton Mile (BTS)

One revenue ton (2,000 pounds) transported one statute mile.


RPK is a measure of an airline’s sales volume and corresponds to number of fare-paying passengers carried muliplied by the number of kilometres flown.


Revenue tonne-kilometre (RTK) is defined as one ton of load (passengers and/ or cargo) carried for one kilometre.

SB (Service Bulletin)

The SB is issued by the aircraft or the equipment manufacturer to provide users with recommendations for modifying or replacing parts or to warn them that a particular check is required.
SB recommendations are not mandatory. Contrary to ADs, SBs do not directly affect aircraft airworthiness.

Scheduled Departure And Arrival Times (BTS)

A takeoff or landing scheduled at an airport, as set forth in published schedules

Scheduled Departure Time (BTS)

The scheduled time that an aircraft should lift off from the origin airport.

Scheduled Departures (BTS)

Takeoffs scheduled at an airport, as set forth in published schedules. (same as Departures Scheduled)

Scheduled Service (BTS)

Transport service operated pursuant to published flight schedules, including extra sections and related non revenue flights.

Scheduled Time Of Arrival (BTS)

The scheduled time that an aircraft should cross a certain point (landing or metering fix).

Schengen Zone

The Schengen Zone, set out in the Treaty of Amsterdam,  allows for the free circulation of population (EU national or otherwise) within a designated zone stretching over the 24 countries of the 27 countries in the European Union and four other non-EU countries that have fully implemented the agreements (Island, Norway, Switzerland and Liechtenstein).  Once a passenger has entered the territory of one of the member states, flights are considered domestic and passengers are  not required to undergo further border controls.

Seat block

Quota of seats allocated for a specific flight  to a travel agent or other carrier by the operating airline.

Seat Mile (BTS)

The aircraft miles flown in each inter-airport segment multiplied by the number of seats available on that segment for revenue passenger use.

Seats Available (BTS)

Installed seats in an aircraft (including seats in lounges) exclusive of any seats not offered for sale to the public by the carrier; provided that in no instance shall any seat sold be excluded from the count of available seats.

Segment (BTS)

A pair of points served or scheduled to be served by a single stage of at least one flight at any given time.

Segmented Trip (BTS)

A trip that includes at least one transfer.


System for allocating aircraft arrival/departure times for each airline.


Period when flight crews remain on call for the airline in the event of unforeseen incidents, sick leave or absenteeism.

Station manager

In charge of supervising operating teams and monitoring activities at the airport, such as passengers, ticketing, information desks or operations.

Summer Schedule

Defined by IATA as the 7-month period running from the last Saturday in March to the last Saturday  in October.

Sustainable Development

Development which meets the needs of the present without compromising the ability of future generations to meet their own (definition supplied in 1987 by the World Commission on Environment and Development in the Brundtland Report).

T-100 (BTS)

A section of Form 41, which includes non-stop segment and on-flight market data. Air carriers are required to periodically file Form 41 with the Bureau of Transportation Statistics.

Taxi-In Time (BTS)

The time elapsed between wheels down and arrival at the destination airport gate.

Taxi-Out Time (BTS)

The time elapsed between departure from the origin airport gate and wheels off.


Used by aircraft and connects from the ramp to the runway or to other airport facilities such as hangars.

Ton Mile (BTS)

One ton (2,000 pounds) transported one statue mile. Ton-miles are computed by multiplying the aircraft miles flown on each inter-airport segment by the number of tons carried on that segment.

Total Itinerary Yield (BTS)

Itinerary fare per itinerary miles flown. The itinerary includes all segments of a journey from origin to destination.

Tour of duty

A tour of duty comprises a series of flight legs (usually 2) flown by a flight crew. In Air France, long-haul tours of duty usually last for 3 days, while on medium-haul they last from 1 to 4 days.

Traffic revenue (Lufthansa)

Revenue generated solely from flight operations. It comprises revenue from transporting passengers and cargo as well as related ancillary services.

Transport-Related Expenses (BTS)

All expense items applicable to the generation of transport-related revenues

Transport-Related Revenues (BTS)

Revenues from the transportation by air of all classes of traffic in scheduled and nonscheduled service.

Travel agent

The travel agent takes bookings on behalf of tour operators or airlines. They receive  “fees” for the services they provide or, more rarely, a commission from the airlines.

Travel Day (BTS)

A 24-hour period from 4:00 a.m. to 3:59 a.m. designated as the reference period for studying trips and travel by members of a sampled household

Turnover (AF-KLM)

AIR FRANCE KLM turnover corresponds to all revenue generated by the AIR FRANCE KLM Group in its three core activities (passenger, cargo, maintenance) and related activities.


Unaccompanied Minor: Children aged between 4 and 12 years old may travel alone. Airlines take charge of the children during the flight. Air France provides this service free of charge


UT Universal Time: Preferred usage for giving times rather than GMT (Greenwich Mean Time). Time zones around the world are described in UTC.

Value Of Shipment (BTS)

The dollar value of the entire shipment. This is defined as the net selling value, f.o.b. plant, exclusive of freight charges, and excise taxes. The value data are displayed in millions of dollars.


Visual Flight Rules: A set of aviation regulations that define the minimum weather conditions needed to fly an aircraft.


Visual Meteorological Conditions: Term used in aviation to define conditions whereby pilots have sufficient visibility (refers to certain visibility minimums, cloud ceilings and clearances) to fly the aircraft according to VFR (visual flight rules), which may vary depending on the airspace.

Warsaw Convention

The Warsaw Convention  was signed on 12 October 1929 and amended in 1933, 1955 and 1966. It governs the transportation of persons, baggage and freight by aircraft in exchange for payment. The Montreal Convention will eventually replace the Warsaw Convention but at the moment they coexist.

Wet lease

A wet lease is a leasing arrangement whereby one airline (lessor) provides an aircraft, complete crew, maintenance, and insurance.

Winter Schedule

Defined by IATA as the 5-month period running from the first Sunday after the last Saturday in October to the Friday preceding the last Saturday in March

Working capital (Lufthansa)

Financial indicator for assessing a company’s liquidity, measured as the difference between its current assets and its current liabilities.

Yield (Lufthansa)

Financial term referring to revenue generated by one fare-paying passenger carrried for one kilometer (RPK).

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