Aviation Revenue Freight Ton-Miles Used in the Transportation Services Index

Friday, November 22, 2024

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

General

Aviation revenue freight ton-miles (RTMFM) data used in the Transportation Services Index (TSI) are from the T-100 dataset 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. 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

Collection

Large U.S. certificated air carriers, small certificated air carriers, commuter air carriers, and all-cargo air carriers must complete Form 41 Financial and Traffic Reporting Requirements. Some carriers complete the form electronically (mainly by the large carriers) and others 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 the data source a frame or a sample?
The T-1 dataset in theory provides information on all U.S. commercial air carriers, except air taxis.
Does the sample cover the entire frame? Or is there some group that is missing or underrepresented in the same 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 reported on is over?
The T-1 data are available to the public about 10 weeks after the month they represent. Given the lag in reporting, BTS forecasts the T-1 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? Are data missing for individual records? If so, how are they identified?
Some data are missing for carriers that fail to report. However, the largest carriers report consistently.

How accurate are the key data fields?
The problem of inaccurate reporting exists but it 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.

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