Flight delay guides & glossary
These short guides explain the definitions behind every figure on RouteOnTime — what "on-time" means in US DOT data, how delay causes are categorized, and how much connection time you really need. Use them alongside the route and airport pages to read the numbers correctly.
All guides
What "on-time" means in US flight data
How the US DOT defines an on-time flight, and why the 15-minute threshold matters when you read delay statistics.
US flight delay causes explainedThe five delay categories the US DOT tracks — carrier, weather, NAS, late-arriving aircraft and security — and what each means for travelers.
How much connection time you really needA practical rule of thumb for minimum connection time based on a route's on-time rate and the hub's delay profile.
Last updated: 2026-06-13