Return to all data sources used in the Bureau of Transportation Statistics’ Transportation Services Index.

General

Aviation revenue passenger-miles (RPM) data used in the Transportation Services Index (TSI) are from the T-100 database compiled by the U.S. Department of Transportation (U.S. DOT), Bureau of Transportation Statistics (BTS), Office of Airline Information (OAI). Airlines submit T-100 data monthly to OAI. OAI processes the submitted data and performs quality checks.

The T-100 databases include data reported by U.S. air carriers operating between airports located within the boundaries of the United States and its territories. These data fields contain information on passengers, freight, and/or mail enplaned at the origin airport and deplaned at the destination airport. The data are available at: https://www.transtats.bts.gov/Data_Elements.aspx?Data=3

Legal Authority

Carriers holding a certificate issued under Section 401 of the Federal Aviation Act of 1958 and that operate aircraft designed for a maximum seating capacity of more than 60 seats or a maximum payload capacity of more than 18,000 pounds or that conduct international operations must report revenue passenger miles to the U.S. DOT.

Pursuant to 14 CFR Part 217 and Part 241, data are collected by OAI within the BTS on Form 41, Schedule T-100.

USDOT instituted the T-100 program January 1, 1990.

Collection

Large U.S. certificated air carriers, small certificated air carriers, and commuter air carriers must complete Form 41 Financial and Traffic Reporting Requirements, either electronically (mainly by the large carriers) or on paper (small and commuter carriers).

The T-100 dataset includes information on all U.S. commercial air carriers, except air taxis. The dataset does not include foreign air carriers, entities that provide commercial services illegally, in-house air transportation (e.g., corporate jets), general aviation, and air taxis.

Data Quality Questions

Coverage/Completeness

• Is this data source a frame or sample?
  The data source is a sample. The T-100 dataset in theory provides information on all U.S. commercial air carriers, except air taxis.
• Does the sample cover the entire frame?  Or is some group missing or underrepresented in the sample?
• The actual data coverage falls short of the theoretical coverage due to carriers failing to report, late reporting, and errors. Reasons for nonreporting include: new carriers that take time to learn the reporting requirements, noncompliance, and lost records. Analysis of the data at the carrier level shows gaps in reporting. However, gaps are rare for the largest carriers, and these carriers account for most of the air transportation services provided. Occasionally, carriers report data after the normal reporting period. Errors may occur in the data even though OAI audits the carrier submissions. For example, a carrier may misreport the number of passengers on a particular route.

Timeliness

• Are the data available monthly?
  Yes.
• How soon are the data available after the month is over?
  The T-100 data are available to the public about 10 weeks after the month they represent.  Given the lag in reporting, BTS forecasts the T-100 data by one month using an ARIMA model to obtain data through the month needed for the TSI.
• Are the data easy to access and use?
  The data are easy to access but require some processing to obtain aggregates.
• Are the microdata available for use?
  Yes, disaggregated carrier data are available

Accuracy

The U.S. DOT Office of the Secretary of Transportation for Policy (OST-X) identified significant reporting problems when small certificated Alaskan air carriers first began reporting in 2002. OAI since has taken steps to improve the accuracy of the data submissions, and OST-X no longer considers this an active area of concern.

Airline traffic and financial data are regulatory data and hence, certified as being correct by the submitting carriers. The data cannot be changed without the carrier's consent. Although BTS can reject data submissions that appear inconsistent, BTS does not have the legal authority to make changes in the data submitted by carriers.

OAI follows up with carriers regarding questionable data. OAI sends back a small fraction of the for carriers to review and resubmit.

• Are there duplicate records?
  No.
• Are there outliers in the data?
  No.
• Are data missing for individual records?  If so, how are they identified?
  Some data are missing for carriers that fail to report. However, largest carriers report consistently.
• How accurate are the key data fields?
  The problem of inaccurate reporting exists but is infrequent.
• Are variances available for this data source?  If so, what method was used to calculate variances?
  No.

Comparability

• Are the data comparable over time within the data source?  If not, can data be made to be comparable (i.e., combining two data series)?
  Beginning in October 2002, monthly data reports included data for carriers that fly aircraft with 60 seats or less or having a payload capacity of 18,000 lbs. or less, as well as domestic all-cargo carriers. These carriers previously reported data quarterly under Form 298c

Other Questions and Important Information

• Is sufficient documentation available for the data source? 
  • Data dictionary:
    Documentation is available in the form of data dictionaries and processing steps but is not available for the audit process conducted by OAI.
  • Detailed description of the methodology:
    Information is not available.
  • Estimation methods:
    Information is not available.
• Are other sources available for the same data?
  Similar data available from the Air Transport Association (ATA) and the Official Airline Guide (OAG).
  Aviation revenue passenger-miles also published on carriers' web sites.
• Who is the contact for the data source?
  Bureau of Transportation Statistics, 1-800-853-1351, answers@bts.gov (link sends e-mail)