Aether-X Port Congestion
Real-time port congestion risk scores, ETA delays and waiting vessels for 15 global ports

Airport codes, distances, routes and passenger numbers as static JSON files.
AirportMiles API is a free Transportation API that requires no API key, is served over HTTPS and supports CORS, so it can be called from the browser.
Airport codes, distances, routes, airlines and passenger numbers as static JSON. No key, no sign-up, open CORS, CC0 airport data. 4,008 airports, 2,785 routes.
Details from airportmiles.com.

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Real-time port congestion risk scores, ETA delays and waiting vessels for 15 global ports
Predictive port congestion, ETA delay and freight volatility signals for 16 global ports
The AirportMiles API is provided by AirportMiles (airportmiles.com). Airport codes, distances, routes, airlines and passenger numbers as static JSON. No key, no sign-up, open CORS, CC0 airport data. 4,008 airports, 2,785 routes.
Yes. The AirportMiles API is listed in the Transportation category of the public-apis directory, which only includes APIs that are free or have a free tier. Check its documentation for rate limits and paid plans.
No. The AirportMiles API requires no authentication, so you can start making requests without signing up.
Yes. The AirportMiles API supports CORS, so front-end JavaScript can call it directly.
Yes. The AirportMiles API is served over HTTPS, so it's safe to use in production.