From April 2017 to May 2017 seasonally-adjusted enplanements on domestic flights increased 0.9 percent while enplanements on U.S. airlines’ international flights to and from the U.S. fell 0.2 percent, resulting in a 0.7 percent systemwide increase (Tables 1, 2, 3).

In one year, from May 2016, seasonally-adjusted enplanements on domestic flights increased 2.6 percent while enplanements on U.S. airlines’ international flights to and from the U.S. rose 6.1 percent, resulting in a 3.1 percent systemwide increase (Tables 1, 2, 3).

In three years, from May 2014, seasonally-adjusted enplanements on domestic flights increased 12.1 percent while enplanements on U.S. airlines’ international flights to and from the U.S. rose 8.5 percent, resulting in a 11.6 percent systemwide increase (Tables 1, 2, 3).

In unadjusted numbers, systemwide, domestic and international  enplanements all reached highs for the month of May (Tables 13, 14, 15).

Trends (Percent changes based on unrounded numbers)

Seasonally-adjusted

Systemwide passenger enplanements (70.9 million) reached a new seasonally-adjusted all-time high, up 0.7 percent from the previous high in April 2017 (70.4 million) (Table 1). Domestic passenger enplanements (61.8 million) reached a new seasonally-adjusted all-time high, up 0.9 percent from the previous high in April 2017 (61.2 million) (Table 2). International passenger enplanements (9.10 million) were down 0.2 percent from the all-time seasonally-adjusted high (9.12 million) reached in April 2017 (Table 3).

Systemwide revenue passenger miles (RPMs) (80.4 billion) reached a new seasonally-adjusted all-time high, up 0.2 percent from the previous high in April 2017 (80.3 billion) (Table 4). Domestic RPMs (56.9 billion) reached a new seasonally-adjusted all-time high, up 0.6 percent from the previous high in April 2017 (56.5 billion) (Table 5). International RPMs (23.6 billion) were down 0.9 percent from the all-time seasonally-adjusted high (23.8 billion) reached in April 2017 (Table 6).

Systemwide available seat-miles (ASMs) (95.9 billion) reached a new seasonally-adjusted all-time high,  up 0.3 percent from the previous high in April 2017 (95.6 billion) (Table 7). Domestic ASMs (66.9 billion) reached a new seasonally-adjusted all-time high,  up 0.3 percent from the previous high in April 2017 (66.7 billion) (Table 8). International ASMs (29.0 billion) reached a new seasonally-adjusted all-time high,  up 0.4 percent from the previous high in April 2017 (28.9 billion) (Table 9).

Systemwide load factor (83.9) was down 0.8 points from the all-time seasonally-adjusted high (84.6) reached in October 2015 (Table 10). Domestic load factor (85.1) was down 0.8 points from the all-time seasonally-adjusted high (85.8) reached in October 2015 (Table 11). International load factor (81.2) was down 2 points from the all-time seasonally-adjusted high (83.1) reached in March 2013 (Table 12).

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 ASMs.

The seasonally-adjusted load factor declined from April (84.0) to May (83.9) despite growth in passenger travel (0.2 percent increase in RPMs) because of more growth in system capacity (0.3 percent increase in ASMs) (Tables 4, 7, 10).

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

Unadjusted

Systemwide passenger enplanements (73.6 million) reached an all-time May high, up 2.9 percent from the previous high (71.5 million) reached in 2016 (Table 13). Domestic passenger enplanements (64.4 million) reached an all-time May high, up 2.6 percent from the previous high (62.8 million) reached in 2016 (Table 14). International passenger enplanements (9.2 million) reached an all-time May high, up 5.4 percent from the previous high (8.8 million) reached in 2016 (Table 15).

Systemwide RPMs (83.5 billion) reached an all-time May high, up 3.4 percent from the previous high (80.8 billion) reached in 2016 (Table 16). Domestic RPMs (59.0 billion) reached an all-time May high, up 3.3 percent from the previous high (57.1 billion) reached in 2016 (Table 17). International RPMs (24.5 billion) reached an all-time May high, up 3.3 percent from the previous high (23.8 billion) reached in 2015 (Table 18).

Systemwide ASMs (99.4 billion) reached an all-time May high, up 3.2 percent from the previous high (96.4 billion) reached in 2016 (Table 19). Domestic ASMs (68.8 billion) reached an all-time May high, up 3.4 percent from the previous high (66.5 billion) reached in 2016 (Table 20). International ASMs (30.6 billion) reached an all-time May high, up 2.6 percent from the previous high (29.8 billion) reached in 2016 (Table 21).

Systemwide load factor (84.0) was down 1.0 points from the all-time May high (85.0) reached in 2014 (Table 22). Domestic load factor (85.7) was down 0.6 points from the all-time May high (86.3) reached in 2014 (Table 23). International load factor (80.1) was down 2.7 points from the all-time May high (82.8) reached in 2013 (Table 24).           

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

Explanation of seasonal adjustment

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 Aug. 1 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. 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 May, 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 May and international numbers through February 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 May, U.S. carriers reported 57,175 foreign point-to-point passengers. For January through May, U.S. carriers reported 302,806 foreign point-to-point passengers.

Data are subject to revision. BTS has scheduled Sept. 15 for the release of June traffic data. None of the data are from samples so measures of statistical significance do not apply.

Seasonally-Adjusted Tables

Passenger Enplanements 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)

Load Factor on U.S. Airlines, Seasonally-Adjusted (Tables 10-12)

Unadjusted Tables

Passenger Enplanements 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)

Load Factor on U.S. Airlines, Unadjusted (Tables 22-24)