The seasonally-adjusted load factor declined from December (83.5) to January (83.3) because system capacity grew faster (0.6 percent increase in Available Seat-Miles (ASMs)) than the growth in passenger travel (0.3 percent increase in Revenue Passenger-Miles (RPMs)) (Tables 4, 7).

Load factor is a measure of the use of aircraft capacity that compares the system use, measured in RPMs as a proportion of system capacity, measured in ASMs.

Without adjusting for seasonal variability, systemwide passenger enplanements (62.5 million) reached an all-time January high, up 2.7 percent from the previous high (60.8 million) reached in 2016 (Table 22).

Trends:

Seasonally-adjusted

Systemwide load factor (83.3) was down 1.3 points from the all-time seasonally-adjusted high (84.6) reached in October 2015 (Table 1). Domestic load factor (84.3) was down 1.4 points from the all-time seasonally-adjusted high (85.7) reached in October 2015 (Table 2). International load factor (80.7) was down 2.5 points from the all-time seasonally-adjusted high (83.3) reached in March 2013 (Table 3).

Systemwide RPMs (79.0 billion) reached a new seasonally-adjusted all-time high, up 0.3 percent from the previous high in December 2016 (78.7 billion) (Table 4). Domestic RPM (56.1 billion) reached a new seasonally-adjusted all-time high, up 0.5 percent from the previous high in November 2016 (55.8 billion) (Table 5). International RPMs (22.9 billion) were down 0.7 percent from the all-time seasonally-adjusted high (23.0 billion) reached in June 2016 (Table 6).

Systemwide ASMs (94.9 billion) reached a new seasonally-adjusted all-time high, up 0.6 percent from the previous high in December 2016 (94.3 billion) (Table 7). Domestic ASMs (66.5 billion) reached a new seasonally-adjusted all-time high, up 0.8 percent from the previous high in December 2016 (66.0 billion) (Table 8). International ASMs (28.3 billion) were down 0.2 percent from the all-time seasonally-adjusted high (28.4 billion) reached in June 2016 (Table 9).

Systemwide passenger enplanements (69.3 million) were down 0.1 percent from the all-time seasonally-adjusted high (69.4 million) reached in November 2016 (Table 10). Domestic passenger enplanements (60.5 million) were down 0.4 percent from the all-time seasonally-adjusted high (60.8 million) reached in November 2016 (Table 11). International passenger enplanements (8.8 million) reached a new seasonally-adjusted all-time high, up 0.7 percent from December 2016 (8.7 million) (Table 12).

Seasonally adjusted trends are for the time period January 2000 to present. Additional data, including domestic and international numbers, can be found on the seasonally-adjusted data  page.

Unadjusted

Systemwide load factor (79.4) was down 0.9 points from the all-time January high (80.3) reached in 2014 (Table 13). Domestic load factor (79.5) was down 1.2 points from the all-time January high (80.7) reached in 2014 (Table 14). International load factor (79.2) was down 0.4 points from the all-time January high (79.6) reached in 2014 (Table 15).

Systemwide RPMs (71.4 billion) reached an all-time January high, up 3.1 percent from the previous high (69.3 billion) reached in 2016 (Table 16). Domestic RPMs (50.1 billion) reached an all-time January high, up 4.2 percent from the previous high (48.1 billion) reached in 2016 (Table 17). International RPMs (21.3 billion) reached an all-time January high, up 0.5 percent from the previous high (21.2 billion) reached in 2016 (Table 18).

Systemwide ASMs (89.9 billion) reached an all-time January high, up 4.1 percent from the previous high (86.3 billion) reached in 2016 (Table 19). Domestic ASMs (63.0 billion) reached an all-time January high, up 3.9 percent from the previous high (60.6 billion) reached in 2008 (Table 20). International ASMs (26.9 billion) reached an all-time January high, up 0.8 percent from the previous high (26.7 billion) reached in 2016 (Table 21).

Systemwide passenger enplanements (62.5 million) reached an all-time January high, up 2.7 percent from the previous high (60.8 million) reached in 2016 (Table 22). Domestic passenger enplanements (54.0 million) reached an all-time January high, up 2.8 percent from the previous high (52.5 million) reached in 2016 (Table 23). International passenger enplanements (8.5 million) reached an all-time January high, up 2.1 percent from the previous high (8.3 million) reached in 2016 (Table 24).

Unadjusted trends are for the time period January 1996 to present. Data are available at Customize Table and can be downloaded from the seasonally-adjusted data  page.

Explanation of seasonal adjustment

Seasonal adjustment allows the comparing of monthly load factors to all other months. When the primary purpose is to examine monthly shifts in transportation services output and analyze short-term trends, the variation introduced by normal seasonal changes must be removed from the data. Transportation is highly seasonal, and without adjustment, the data do not give an accurate picture of underlying changes in aviation, passenger travel.

Seasonal adjustment of the data removes the seasonal events that follow a regular seasonal pattern. Changes that are not due to seasonality, such as a change in air travel resulting from economic conditions become more readily apparent.

The aviation data are seasonally adjusted for the effects of trading day, moving holidays, and data outliers.

See Seasonal Adjustment for methodology and additional explanation.

Reporting Notes

Data are compiled from monthly reports filed with BTS by commercial U.S. air carriers detailing operations, passenger traffic and freight traffic. This release includes data received by BTS from 81 carriers as of April 10 for U.S. carrier scheduled civilian operations.

Go to http://www.transtats.bts.gov/releaseinfo.asp for the complete list of reporting and non-reporting carriers. U.S. carriers’ foreign point-to-point flights are included in system and international totals. To create a customized table for passengers, flights, RPMs, ASMs and other data, including non-scheduled service, go to https://www.transtats.bts.gov/TRAFFIC/

For additional scheduled service numbers for U.S. airlines, U.S. and foreign airlines, by airline and by airport, see Passengers, Flights, Revenue Passenger-Miles, Available Seat-Miles and Load Factor.

Traffic numbers are available on the BTS website at TranStats, the Intermodal Transportation Database, at http://transtats.bts.gov.  Click on “Aviation.”  For systemwide passengers, RPMs and ASMs by carrier through January, click on “Air Carrier Summary Data (Form 41 and 298C Summary Data),” and then click on “Schedule T-1.” Use crosstabs to find scheduled service.

For domestic numbers through January and international numbers through October by origin as well as by carrier, click on “Aviation,” then click on “Air Carrier Statistics (Form 41 Traffic).”  Click on “T-100 Market” for system passenger numbers, “T-100 Domestic Market” for domestic or “T-100 International Market” for international.  For flights, stage length and trip length, use the appropriate T-100 Segment database. Use crosstabs to find scheduled service.

International totals in this press release consist of all U.S. carrier operations to and from the U.S. and from one foreign point to another foreign point. TranStats T-100 systemwide and international totals do not include U.S. carriers’ foreign point-to-point flights. For January, U.S. carriers reported 60,490 foreign point-to-point passengers.

Data are subject to revision. BTS has scheduled May 11 for the release of February traffic data. None of the data are from samples so measures of statistical significance do not apply.

Seasonally-Adjusted Tables

Load Factor on U.S. Airlines, Seasonally-Adjusted (Tables 1-3)

Revenue Passenger-Miles on U.S. Airlines, Seasonally-Adjusted (Tables 4-6)

Available Seat-Miles on U.S. Airlines, Seasonally-Adjusted (Tables 7-9)

Passenger Enplanements on U.S. Airlines, Seasonally-Adjusted (Tables 10-12)

Unadjusted Tables

Load Factor on U.S. Airlines, Unadjusted (Tables 13-15)

Revenue Passenger-Miles on U.S. Airlines, Unadjusted (Tables 16-18)

Available Seat-Miles on U.S. Airlines, Unadjusted (Tables 19-21)

Passenger Enplanements on U.S. Airlines, Unadjusted (Tables 22-24)