Reference metadata describe statistical concepts and methodologies used for the collection and generation of data. They provide information on data quality and, since they are strongly content-oriented, assist users in interpreting the data. Reference metadata, unlike structural metadata, can be decoupled from the data.
Economic Statistics Department / Sectoral Business Statistics Unit
Departamento de Estatísticas Económicas / Serviço de Estatísticas Setoriais das Empresas
1.3. Contact name
Restricted from publication
1.4. Contact person function
Restricted from publication
1.5. Contact mail address
Av. Antonio José de Almeida 2 PT-1000-043-Lisboa Portugal
1.6. Contact email address
Restricted from publication
1.7. Contact phone number
Restricted from publication
1.8. Contact fax number
Restricted from publication
2.1. Metadata last certified
21 January 2025
2.2. Metadata last posted
21 January 2025
2.3. Metadata last update
21 January 2025
3.1. Data description
The air transport statistics are compiled and transmitted to Eurostat by Statistics Portugal (Instituto Nacional de Estatística) on a monthly and annual basis (depending on the dataset category). The data collection follows the provisions of the following EU legal acts:
Regulation (EC) No 437/2003 of the European Parliament and of the Council of 27 February 2003 on statistical returns in respect of the carriage of passengers, freight and mail by air;
Regulation (EC) No 1358/2003, implementing Regulation (EC) No 437/2003 of the European Parliament and of the Council on statistical returns returns in respect of the carriage of passengers, freight and mail by air and amending Annexes I and II thereto.
Three data sets required by the Regulation – A1, B1 and C1 – are provided to Eurostat:
Dataset A1 - Flight Stage dataset: periodic flight stage data registered for airport-to-airport routes, and broken down by arrivals/departures, scheduled/non-scheduled, passenger service/all-freight and mail service, airline information and aircraft type. The values provided concern passengers on board, freight and mail on board, commercial air flights as well as passenger seats available.
Dataset B1 - On Flight Origin/Destination dataset: periodic on flight origin/destination data registered for airport-to-airport routes, and broken down by arrivals/departures, scheduled/non scheduled, passenger service/all-freight and mail service and airline information. The values provided concern passengers carried and freight and mail loaded or unloaded.
Dataset C1 - Airport dataset: periodic airport data registered for declaring airports. The values provided concern total passengers carried, total direct transit passengers, total transfer (indirect transit) passengers (optional variable), total freight and mail loaded or unloaded, total commercial aircraft movements and total aircraft movements.
Data sets A1 and B1 are provided monthly, while data set C1 is provided annually, on a monthly basis, including the optional variable - total number of transfer passengers.
Empty leg flights or technical stops are not transmitted to Eurostat and the number of passengers includes infants in arms.
3.2. Classification system
Airports are classified according to ICAO (International Civil Aviation Organization) airport coded as listed in ICAO document 7910.
Aircrafts are classified according to aggregated aircraft categories based on the ICAO aircraft codes as listed in ICAO document 8643.
Airlines are classified according to the ICAO airline codes as listed in the ICAO document 8585. When providing the data to Eurostat, the region where they are licensed is coded accordingly either as European Union (EU) or outside the European Union (non-EU).
3.3. Coverage - sector
Air transport - commercial air services and civil aircraft movements for all national airports.
3.4. Statistical concepts and definitions
The main concepts used in this domain are the following:
Community airport - adefined area on land or water in a Member State subject to the provisions of the treaty, which is intended to be used either wholly or in part for the arrival, departure and surface movement of aircraft and open for commercial air services.
Flight stage - the operation of an aircraft from take-off to its next landing. This is linked to the definition of passengers (or freight and mail) on board.
Passengers on board - all passengers on board of the aircraft upon landing at the reporting airport or at taking off from the reporting airport. All revenue and non-revenue passengers on board an aircraft during a flight stage. Includes direct transit passengers (counted at arrivals and departures).
Direct transit passengers - passengers who, after a short stop, continue their journey on the same aircraft on a flight having the same flight number as the flight on which they arrive.
Transfer of indirect transit passengers - passengers arriving and departing on a different aircraft within 24 hours, or on the same aircraft bearing different flight numbers. They are counted twice: once upon arrival and once on departure.
Freight and mail on board - all freight and mail on board of the aircraft upon landing at the reporting airport or at taking off from the reporting airport. All freight and mail on board an aircraft during a flight stage. Includes direct transit freight and mail (counted at arrivals and departures). Includes express services and diplomatic bags. Excludes passenger baggage.
On flight origin and destination - traffic on a commercial air service identified by a unique flight number subdivided by airport pairs in accordance with point of embarkation and point of disembarkation on that flight. For passengers, freight or mail where the airport of embarkation is not known, the aircraft origin should be deemed to be the point of embarkation; similarly, if the airport of disembarkation is not known, the aircraft destination should be deemed to be the point of disembarkation. This is linked to the definition of passengers carried and freight and mail loaded or unloaded.
Passengers carried - all passengers on a specific flight (with one flight number) counted once only and not repeatedly on each individual stage of that flight. All revenue and non-revenue passengers whose journey begin or terminates at the reporting airport and transfer passengers joining or leaving the flight at the reporting airport. Excludes direct transit passengers.
Freight and mail loaded or unloaded - all freight and mail loaded onto or unloaded from an aircraft. Includes express services and diplomatic bags. Excludes passenger baggage. Excludes direct transit freight and mail.
Passenger unit - one passenger unit is equivalent to either one passenger or 100 kilograms of freight and mail.
3.5. Statistical unit
The data are collected at individual airport level.
3.6. Statistical population
Four categories of Community airports are defined by the Regulation (EC) N°1358/2003:
Category "0": Airports with less than 15 000 passenger units per year are considered as having only "occasional commercial traffic" without obligation to report;
Category "1": Airports with between 15 000 and 150 000 passenger units per year shall transmit only aggregated airport data (Data set C);
Category "2": Airports with more than 150 000 passenger units and less than 1 500 000 passenger units per year shall transmit flight stage data, on flight origin destination data as well as aggregated airport data (Data sets A, B and C);
Category "3": Airports with at least 1 500 000 passenger units per year shall transmit flight stage data, on flight origin destination data as well as aggregated airport data (Data sets A, B and C).
3.7. Reference area
Commercial airports located in Portugal.
3.8. Coverage - Time
Annual data on passengers carried available as from 1993. Annual data on passenger on-board and number of flights available as from 1996. Annual data on airport traffic (passengers carried, freight and mail loaded and unloaded, aircraft movements) available as from 2001. Quarterly and annual data on passenger airport traffic as well as on freight and mail loaded and unloaded available as from 2001. Monthly airport traffic data on passenger and freight transport (according to the regulation, dataset C1) available as from reference year 2003. Monthly transfer passenger data (optional variable provided in dataset C1) available as from reference year 2017.
3.9. Base period
Not applicable.
The units used depend on the variables collected within each data set and are: number of passengers, tonnes, aircraft movements and passenger seats available. The weight of freight and mail is transmitted in tonnes with three decimal places.
Data is collected on a monthly basis.
6.1. Institutional Mandate - legal acts and other agreements
European level: until 2002, the data were provided to Eurostat on a voluntary basis; since 2002 data provision is based on an EP and Council framework legal act and on several implementing Commission Regulations:
Regulation (EC) No 223/2009 on European statistics (recital 24 and Article 20(4)) of 11 March 2009 (OJ L 87, p. 164), stipulates the need to establish common principles and guidelines ensuring the confidentiality of data used for the production of European statistics and the access to those confidential data with due account for technical developments and the requirements of users in a democratic society.
7.2. Confidentiality - data treatment
The airline identification is the only information being treated. Before providing data to Eurostat, the region where the airline is licensed is coded according to Europen Union (EU) or non-European Union (non-EU).
8.1. Release calendar
Since July 2020, preliminary results are published monthly, nearly 45 days after the reference month.
Release dates are publicly available in the release calendar of the NSI.
8.2. Release calendar access
The release calendar is publicly available on the website of the NSI.
8.3. Release policy - user access
The data are disseminated to all users at the same time, through the Statistics Portugal website.
The data are released simultaneously to all interested parties by issuing a press release and updating the information on the database of Indicators, both available in Portuguese and English.
A calendar of dissemination is available at beginning of each year. If there are changes on dates, an explanation is presented, and the calendar is adjusted accordingly.
Since July 2020, preliminary results are published monthly, nearly 45 days after the reference month.
Annual results (final results) are published in November (N+1).
10.1. Dissemination format - News release
Since July 2020, preliminary results are published monthly (nearly 45 days after the reference month) in the format of a press release.
10.2. Dissemination format - Publications
The final results are published annualy in the format of a Publication.
10.3. Dissemination format - online database
Monthly preliminary results can be found on database of NSI (nearly 45 days after the reference month).
Statistics Portugal has adopted the European Statistics Code of Practice, since its first edition (2005), as firm guidance for the success of its mission. Since its last revision (November 2017), the Code comprises the Quality Declaration of the European Statistical System, 16 Principles and 84 indicators of best practices and standards for each of the Principles, defining the European benchmarks for the statistical activity, covering the institutional environment, statistical processes, and statistical outputs. Although all 16 principles are essential, it is important to highlight the Principle 4: Commitment to Quality.
The Quality Assurance Framework (QAF) is a useful tool in implementing the Code of Practice in the member states, recommending possible actions at the institutional and process level for each of the Code’s indicators.
In the framework of its mission and in line with the Code of Practice, Statistics Portugal (SP) follows reliable and robust methodologies and adequate procedures, according to the best international practices. It also maintains and makes public an extensive set of documentation on concepts and classifications, included on its Integrated Metadata System, as an important and constant groundwork for its activity. Moreover, SP produces and disseminates statistics in an impartial, objective and transparent manner and treats all users equally, in agreement with its Dissemination Policy. All these aspects have a positive impact on the credibility of the produced statistics and the perceived quality and trust of the institution as a whole.
SP’s quality commitment is clearly and publicly stated and is an essential aspect in conveying the trustworthiness of Portuguese official statistics. With this goal in mind, SP’s latest version of its Quality Chart, released in 2019, establishes SP’s public commitment.
Statistical Production Processes Handbook - Summary
Consult EUROSTAT’s Quality webpage for further information on implementing the European Statistics Code of Practice in the ESS and at EUROSTAT, as well as on the rounds of Peer Reviews, on European quality policies (Quality Declaration of the ESS) and on Quality reports.
11.2. Quality management - assessment
There is a set of validation rules and quality checks put in place, which detects various types of issues.
The new version of Edamis for validation datasets allows us to correct any structural errors before data submission.
Annually, Eurostat provides a data quality report with a summary of the main findings affecting quality. Mirror checks and checks for consistency over time are prepared as well. Statistics Portugal analyses and, if necessary, submit revisions.
12.1. Relevance - User Needs
The key users of air transport statistics collected according to the Regulation 437/2003 are:
Public Administration
Ministry of Transports
Universities and research institutions
Companies (Services and Transport)
Other users
Data of commercial aircraft movements, routes, number of passengers, amount of transported freight and mail as well as seats available provides an important basis for decision-making of politics, society and economy in the context of the development and promotion of transport projects.
12.2. Relevance - User Satisfaction
Statistics Portugal conducts a general and regular user satisfaction survey for internal evaluation. There is no user survey especially on air transport statistics users.
12.3. Completeness
The collection of data on air transport statistics is carried out in accordance with the provisions of Regulation 437/2003. All variables in all three data sets are provided including the voluntary variable - transfer passenger.
13.1. Accuracy - overall
Overall accuracy of the air transport statistics data is good. The processing with several plausibility checks, as well as checks done before transmitting data to Eurostat provides a high accuracy of the data. Comparisons with published data by the airports as well as mirror checks for national flights are regularly made and show a good level of comparability.
13.2. Sampling error
Not applicable for air transport data collection.
13.3. Non-sampling error
Not applicable for air transport data collection.
14.1. Timeliness
All the statistics required by the provisions of the Regulation 437/2003 are transmitted to Eurostat approximately 2 months after the reference month.
14.2. Punctuality
Air transport statistics were published without delay in relation to the scheduled date.
15.1. Comparability - geographical
There are no problems of comparability for air transport data collection with a very high data comparability across countries, due to the common legal basis.
Comparisons of the data regarding passengers and freight/mail declared by partner reporting airports (so-called mirror checks) by Eurostat allow further the detection of possible inconsistencies which can be corrected if possible.
15.2. Comparability - over time
As from 2002 the statistics on air transport are comparable over time, as they are collected following fully the provisions of the legal act – the Regulation 437/2003. Time series checks are regularly made to detect inconsistencies in the data.
Detailed information on eventual breaks in the time series are provided in the Country Specific Notes (CSNs).
15.3. Coherence - cross domain
Comparisons with other transport statistics are only partially and to a limited extent possible with regard to freight transport and passenger transport, since data are currently not available or are not collected at the same level of detail and also different methods and underlying objectives.
15.4. Coherence - internal
Coherence between datasets is good.
Mirror and missing routes checks provided by Eurostat allow the identification of possible inconsistencies, that are corrected as far as possible.
Data colletion is held by ANA airports and ANAC – National Civil Aviation Authority.
Since July 2020, preliminary results are published monthly (nearly 45 days after the reference month).
Revision may be required if an error is identified or in consequence of the "mirror checks" reports that allow to compare the data declared by partner reporting airports and find possible inconsistencies that are corrected as far as possible.
In case of any data change in the statistics after the annual results (final results) have been published, the public is informed in a form of an official notice (in case of data change in the Press Release) or footnotes (in case of pdf publications or on-line tables).
18.1. Source data
Dataset A1 – Data Suppliers (Passengers on board/Freight and mail on board):
ANA airports ANAC – National Civil Aviation Authority (for other airports)
Dataset B1 –Data Suppliers (Passengers carried/Freight and mail loaded/unloaded):
ANA airports ANAC – National Civil Aviation Authority (for other airports)
Datasets A1 and B1 - Use of Air Waybill Data as information source of freight data: Not applicable
Dataset C1 – Bodies that supply the direct transit information to the CNA: From the airports data systems
Dataset C1 – Bodies that supply the commercial and total aircraft movement to the CNA:
ANA airports ANAC – National Civil Aviation Authority (for other airports)
18.2. Frequency of data collection
Information needed for the data sets A1, B1 and C1 are collected on monthly basis.
18.3. Data collection
Dataset A1 – Data supplier’s information sources (Passengers on board/ Freight and mail on board):
From the airports data systems (both directly from airlines and electronic movement messages to the airport).
Dataset A1 – Data transmission to CNA – level of aggregation, system and periodicity (Passengers on board/ Freight and mail on board):
Individual flight, monthly basis by cloud or by e-mail.
Dataset B1 – Data supplier’s information sources (Passengers carried/ Freight and mail loaded/unloaded):
From the airports data systems (both directly from airlines and electronic movement messages to the airport).
Dataset B1 – Data transmission to CNA – level of aggregation, system and periodicity(Passengers carried/ Freight and mail loaded/unloaded): Individual flight, monthly basis by cloud or by e-mail.
Datasets A1 and B1 - OFOD data derived from FS data or collected separately by the data supplier: It’s derived from the FS data.
Implementation of the data collection and compilation process: An all new data collection.
18.4. Data validation
Data validation procedure:
All the main validation procedures are performed directly on the airports information systems.
At Statistics Portugal only basic checks are made: mirror checks (if possible), aggregate analysis on the main identification fields (by airport, by main air carriers, etc.), codes of airports, airlines and aircrafts (validation based on codes lists provided by EUROSTAT) and seats available (validation based on tables considering the aircraft type provided by EUROSTAT).
18.5. Data compilation
After various plausibility checks, the data are compiled into monthly data following the structure of the data sets which are preset by regulation (EC) 1358/2003 and detailed in the reference manual on air transport statistics.
18.6. Adjustment
Not applicable.
No comments.
The air transport statistics are compiled and transmitted to Eurostat by Statistics Portugal (Instituto Nacional de Estatística) on a monthly and annual basis (depending on the dataset category). The data collection follows the provisions of the following EU legal acts:
Regulation (EC) No 437/2003 of the European Parliament and of the Council of 27 February 2003 on statistical returns in respect of the carriage of passengers, freight and mail by air;
Regulation (EC) No 1358/2003, implementing Regulation (EC) No 437/2003 of the European Parliament and of the Council on statistical returns returns in respect of the carriage of passengers, freight and mail by air and amending Annexes I and II thereto.
Three data sets required by the Regulation – A1, B1 and C1 – are provided to Eurostat:
Dataset A1 - Flight Stage dataset: periodic flight stage data registered for airport-to-airport routes, and broken down by arrivals/departures, scheduled/non-scheduled, passenger service/all-freight and mail service, airline information and aircraft type. The values provided concern passengers on board, freight and mail on board, commercial air flights as well as passenger seats available.
Dataset B1 - On Flight Origin/Destination dataset: periodic on flight origin/destination data registered for airport-to-airport routes, and broken down by arrivals/departures, scheduled/non scheduled, passenger service/all-freight and mail service and airline information. The values provided concern passengers carried and freight and mail loaded or unloaded.
Dataset C1 - Airport dataset: periodic airport data registered for declaring airports. The values provided concern total passengers carried, total direct transit passengers, total transfer (indirect transit) passengers (optional variable), total freight and mail loaded or unloaded, total commercial aircraft movements and total aircraft movements.
Data sets A1 and B1 are provided monthly, while data set C1 is provided annually, on a monthly basis, including the optional variable - total number of transfer passengers.
Empty leg flights or technical stops are not transmitted to Eurostat and the number of passengers includes infants in arms.
21 January 2025
The main concepts used in this domain are the following:
Community airport - adefined area on land or water in a Member State subject to the provisions of the treaty, which is intended to be used either wholly or in part for the arrival, departure and surface movement of aircraft and open for commercial air services.
Flight stage - the operation of an aircraft from take-off to its next landing. This is linked to the definition of passengers (or freight and mail) on board.
Passengers on board - all passengers on board of the aircraft upon landing at the reporting airport or at taking off from the reporting airport. All revenue and non-revenue passengers on board an aircraft during a flight stage. Includes direct transit passengers (counted at arrivals and departures).
Direct transit passengers - passengers who, after a short stop, continue their journey on the same aircraft on a flight having the same flight number as the flight on which they arrive.
Transfer of indirect transit passengers - passengers arriving and departing on a different aircraft within 24 hours, or on the same aircraft bearing different flight numbers. They are counted twice: once upon arrival and once on departure.
Freight and mail on board - all freight and mail on board of the aircraft upon landing at the reporting airport or at taking off from the reporting airport. All freight and mail on board an aircraft during a flight stage. Includes direct transit freight and mail (counted at arrivals and departures). Includes express services and diplomatic bags. Excludes passenger baggage.
On flight origin and destination - traffic on a commercial air service identified by a unique flight number subdivided by airport pairs in accordance with point of embarkation and point of disembarkation on that flight. For passengers, freight or mail where the airport of embarkation is not known, the aircraft origin should be deemed to be the point of embarkation; similarly, if the airport of disembarkation is not known, the aircraft destination should be deemed to be the point of disembarkation. This is linked to the definition of passengers carried and freight and mail loaded or unloaded.
Passengers carried - all passengers on a specific flight (with one flight number) counted once only and not repeatedly on each individual stage of that flight. All revenue and non-revenue passengers whose journey begin or terminates at the reporting airport and transfer passengers joining or leaving the flight at the reporting airport. Excludes direct transit passengers.
Freight and mail loaded or unloaded - all freight and mail loaded onto or unloaded from an aircraft. Includes express services and diplomatic bags. Excludes passenger baggage. Excludes direct transit freight and mail.
Passenger unit - one passenger unit is equivalent to either one passenger or 100 kilograms of freight and mail.
The data are collected at individual airport level.
Four categories of Community airports are defined by the Regulation (EC) N°1358/2003:
Category "0": Airports with less than 15 000 passenger units per year are considered as having only "occasional commercial traffic" without obligation to report;
Category "1": Airports with between 15 000 and 150 000 passenger units per year shall transmit only aggregated airport data (Data set C);
Category "2": Airports with more than 150 000 passenger units and less than 1 500 000 passenger units per year shall transmit flight stage data, on flight origin destination data as well as aggregated airport data (Data sets A, B and C);
Category "3": Airports with at least 1 500 000 passenger units per year shall transmit flight stage data, on flight origin destination data as well as aggregated airport data (Data sets A, B and C).
Commercial airports located in Portugal.
Data is collected on a monthly basis.
Overall accuracy of the air transport statistics data is good. The processing with several plausibility checks, as well as checks done before transmitting data to Eurostat provides a high accuracy of the data. Comparisons with published data by the airports as well as mirror checks for national flights are regularly made and show a good level of comparability.
The units used depend on the variables collected within each data set and are: number of passengers, tonnes, aircraft movements and passenger seats available. The weight of freight and mail is transmitted in tonnes with three decimal places.
After various plausibility checks, the data are compiled into monthly data following the structure of the data sets which are preset by regulation (EC) 1358/2003 and detailed in the reference manual on air transport statistics.
Dataset A1 – Data Suppliers (Passengers on board/Freight and mail on board):
ANA airports ANAC – National Civil Aviation Authority (for other airports)
Dataset B1 –Data Suppliers (Passengers carried/Freight and mail loaded/unloaded):
ANA airports ANAC – National Civil Aviation Authority (for other airports)
Datasets A1 and B1 - Use of Air Waybill Data as information source of freight data: Not applicable
Dataset C1 – Bodies that supply the direct transit information to the CNA: From the airports data systems
Dataset C1 – Bodies that supply the commercial and total aircraft movement to the CNA:
ANA airports ANAC – National Civil Aviation Authority (for other airports)
Since July 2020, preliminary results are published monthly, nearly 45 days after the reference month.
Annual results (final results) are published in November (N+1).
All the statistics required by the provisions of the Regulation 437/2003 are transmitted to Eurostat approximately 2 months after the reference month.
There are no problems of comparability for air transport data collection with a very high data comparability across countries, due to the common legal basis.
Comparisons of the data regarding passengers and freight/mail declared by partner reporting airports (so-called mirror checks) by Eurostat allow further the detection of possible inconsistencies which can be corrected if possible.
As from 2002 the statistics on air transport are comparable over time, as they are collected following fully the provisions of the legal act – the Regulation 437/2003. Time series checks are regularly made to detect inconsistencies in the data.
Detailed information on eventual breaks in the time series are provided in the Country Specific Notes (CSNs).
