Seat supply and passenger traffic across three and a half decades, at two measurement scopes: demand grew faster than capacity, so planes fly far fuller now.
What this shows: The chart covers 1990 Q1 to 2025 Q3. It plots Available seat-miles (ASM): US system-wide (all carriers reporting to BTS, including international legs), Available seat-miles (ASM): US domestic (US-to-US legs), Revenue passenger-miles (RPM): US system-wide (all carriers reporting to BTS, including international legs), Revenue passenger-miles (RPM): US domestic (US-to-US legs) and Load factor (%): system-wide (RPM/ASM) on a vertical axis of Seat-miles and passenger-miles (billions). Latest values: Available seat-miles (ASM): US system-wide (all carriers reporting to BTS, including international legs) 519.9; Available seat-miles (ASM): US domestic (US-to-US legs) 248.7; Revenue passenger-miles (RPM): US system-wide (all carriers reporting to BTS, including international legs) 434.6; Revenue passenger-miles (RPM): US domestic (US-to-US legs) 208.1; Load factor (%): system-wide (RPM/ASM) 83.6. Data run through 2025 Q3.
Conditions and method
The chart plots two scopes. ‘US system-wide’ is every flight leg in the federal carrier traffic data (T-100), domestic and international, of every carrier that reports: about 47% of its 1990-2025 seat-miles are on non-domestic legs and about 28% are flown by foreign carriers. ‘US domestic’ is the legs with both ends in the United States.
A third scope, all worldwide flying by US carriers, is not plotted. Its seat-miles grew 1.63% a year over 1990-2019, between the system-wide 2.01% and the domestic 1.20%.
The domestic share of system-wide seat-miles went from 47.2% in 2019 to 63.4% in 2021 and back to 50.4% in 2023. The recovery slope of the system-wide series after 2020 is therefore partly a change in mix, as international legs collapsed and then returned, and not like-for-like growth in capacity.
Load factor here is passenger-miles over seat-miles, not the share of seats filled. Only the system-wide load factor is plotted. It ran 0.4 to 2.3 percentage points below the domestic one across 2010-2019 and 7.8 points below it in 2021.