One-Month Estimate: Estimated September 2018 to estimated October 2018 domestic enplanements increased 0.2 percent while enplanements on international flights to and from the U.S. fell 0.1 percent for a 0.1 systemwide increase.

One-Year Estimate: Reported October 2017 domestic enplanements to estimated October 2018 domestic enplanements rose 4.8 percent while international enplanements rose 2.4 percent for a 4.5 percent systemwide increase.

Three-Year Estimate: Reported October 2015 domestic enplanements to estimated October 2018 domestic enplanements rose 11.5 percent while international enplanements rose 6.9 percent for a 11.0 percent systemwide increase.

Unadjusted Estimate: Systemwide, domestic, and international enplanements reached estimated highs for the month of October compared to reported data for the previous years.

For September and October estimated data and for reported data through August, see accompanying tables. For the complete database of reported data, see Traffic.

Additional Bureau of Transportation Statistics (BTS) air traffic data:

Seasonally-adjusted

New seasonally-adjusted all-time highs in October 2018

Available seat-miles: Systemwide, domestic, and international available seat miles (ASMs) reached new estimated seasonally-adjusted all-time highs compared to reported data through August.

Load Factor

Estimated systemwide load factor (84.4) was estimated down 0.5 points from the all-time seasonally-adjusted high (84.9) reported in July 2018. Estimated domestic load factor (85.4) was estimated down 0.5 points from the all-time seasonally-adjusted high (85.9) reported in July 2018. Estimated international load factor (81.7) was estimated down 1.4 points from the all-time seasonally adjusted high (83.1) reached in March 2013.

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 estimated seasonally-adjusted load factor declined from September (84.8) to October (84.4) despite estimated growth in passenger travel (0.4 percent increase in RPMs) because estimated system capacity grew faster (0.9 percent increase in ASMs).

Seasonally-adjusted trends are for the time period January 2000 to present based on data reported by U.S. airlines through August and BTS estimates for the two most recent months. Additional data, including domestic and international numbers, can be found on the seasonally-adjusted data  page.

Unadjusted Trends

Estimated October unadjusted all-time highs

Passenger enplanements: Estimated systemwide, domestic, and international passenger enplanements reached new highs for the month of October compared to reported data for previous years.

One-Month Estimate: Estimated September 2018 to estimated October 2018 domestic enplanements increased 6.7 percent while enplanements on international flights to and from the U.S. fell 2.6 percent for a 5.6 systemwide increase.

One-Year Estimate: Reported October 2017 domestic enplanements to estimated October 2018, domestic enplanements rose 4.7 percent while international enplanements rose 1.8 percent for a 4.4 systemwide increase

Three-Year Estimate: Reported October 2015 domestic enplanements to estimated October 2018, domestic enplanements rose 11.1 percent while international enplanements rose 4.9 percent for a 10.4 systemwide increase

Revenue passenger-miles: Systemwide, domestic, and international revenue passenger miles (RPMs) reached new estimated highs for the month of October compared to reported data for previous years.

Available seat-miles: Systemwide, domestic, and international available seat miles (ASMs) reached new estimated highs for the month of October compared to reported data for previous years.

Load Factor:           

Estimated systemwide load factor (84.1) was down 0.9 points from the all-time October high for reported data reached in 2015 (85.0). Domestic load factor (85.7) was down 0.7 points from the all-time October high (86.4) reached in 2015. International load factor (80.1) was down 2.3 points from the all-time October high (82.4) reached in 2010.

Unadjusted load factor rose from the reported October 2017 (83.6) to the estimated October 2018 (84.1) because estimated passenger travel grew faster (5.2 percent increase in RPMs) than estimated system capacity (4.6 percent increase in ASMs).

Unadjusted trends are for the time period January 1996 to present based on data reported by U.S. airlines through August and BTS estimates for the two most recent months. Data through August are available at Customize Table. Reported data and estimates for the two most recent months can be downloaded from the seasonally-adjusted data  page.

U.S. Airlines Reported Data for August

Seasonally Adjusted: U.S. airlines carried 75.1 million systemwide (domestic and international) scheduled service passengers, seasonally-adjusted, in August 2018 down 0.6 percent from July.

One Month: July 2018 to August 2018 domestic enplanements declined 0.6 percent while enplanements on international flights to and from the U.S. declined 0.8 percent for a 0.6 percent systemwide seasonally-adjusted decline.

One Year: August 2017 to August 2018 domestic enplanements rose 5.4 percent while international enplanements rose 2.0 percent for a 5.0 percent systemwide seasonally-adjusted increase.

Three Years: August 2015 to August 2018 domestic enplanements rose 11.8 percent while international enplanements rose 7.3 percent for a 11.2 percent systemwide seasonally-adjusted increase.

Unadjusted: Systemwide, domestic, and international enplanements all reached all-time highs for the month of August.

One Month: Domestic enplanements declined 2.9 percent while enplanements on international flights to and from the U.S. declined 6.7 percent for a 3.5 percent systemwide unadjusted decline from July 2018 to August 2018.

One Year: Domestic enplanements rose 5.7 percent while international enplanements rose 2.1 percent for a 5.2 percent systemwide unadjusted increase from August 2017 to August 2018.

Three Years: Domestic enplanements rose 12.2 percent while international enplanements rose 5.5 percent for a 11.3 percent systemwide unadjusted increase August 2015 to August 2018.

Explanation of estimates

Estimates are derived from a forecast of the data. The first estimate is a 2-month ahead forecast of the data. When an additional month of data become available, BTS uses the data to re-forecast the month and releases a second estimate. BTS performs the forecasting using the Census X-12 procedure in SAS – a statistical software program.

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 80 U.S. carriers as of Nov. 7 for U.S. carrier scheduled civilian operations.

See the BTS Airlines and Airports page for additional scheduled service numbers through August for U.S. and foreign airlines. International data by origin and destination are available through May.

BTS has scheduled Dec. 13 for the release of the first estimate of November air traffic data, the second estimate of the October air traffic data and reported data through September.

None of the data are from samples. Measures of statistical significance do not apply to the complete air traffic data.