# Airline Route Traffic API – US Passengers, Seats and Cargo by Route: findings

3 posts built from the [Airline Route Traffic API – US Passengers, Seats and Cargo by Route](https://pushbuild.com/apis/airline-route-traffic.html).

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Flights · 2026-11-07

### [Southwest left a quarter of its domestic seats empty in 2025](https://pushbuild.com/apis/analysis/airline-load-factor-2025/)

Southwest filled 74.3% of its domestic seats in 2025, the lowest of any large US airline; Delta filled…

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Flights · 2026-11-07

### [The routes that vanished, and the ones that doubled](https://pushbuild.com/apis/analysis/air-routes-that-vanished-or-doubled/)

Newark–Chicago Midway went from 322,232 passengers in 2019 to 10,282 in 2025 (-96.8%). Bozeman–Denver went from 306,176 to 667,832 (+118%), and…

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Flights · 2026-11-07

### [What were the busiest US domestic air routes in 2025?](https://pushbuild.com/apis/analysis/busiest-domestic-air-routes-vs-2019/)

New York JFK–Los Angeles was the busiest US domestic route in 2025, with 2,912,963 passengers, followed by LaGuardia–Chicago O'Hare (2,769,621) and…

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As of 2026-11-07. Source: https://pushbuild.com/apis/analysis/api/airline-route-traffic/