Methodology

The data source

Every statistic on FlightRecord is computed from the Reporting Carrier On-Time Performance dataset published by the US Department of Transportation’s Bureau of Transportation Statistics (BTS). US airlines above a revenue threshold are required by law to report the actual departure and arrival time of every domestic flight they operate. This site currently covers 14,111,289 flights across 24 months, 2024-06 through 2026-05.

We use the bulk monthly files exactly as published — no sampling, no third-party feeds, no estimates. Airport names and locations come from the public-domain OurAirports dataset.

Definitions

• On-time — a flight that arrived less than 15 minutes after its scheduled arrival time. This is the official DOT definition. The on-time percentage is computed over non-cancelled flights; diverted flights (which never arrive at their scheduled destination on schedule) count against it.
• Average delay — the mean of ArrDelayMinutes across completed (non-cancelled, non-diverted) flights. Early arrivals count as zero delay, so this is a conservative figure.
• Cancellation rate — cancelled flights divided by all scheduled flights. Cancelled and diverted flights are excluded from delay averages but always reported separately.
• Delay causes— for flights arriving 15+ minutes late, carriers report how the delay splits across five categories (carrier, weather, National Airspace System, security, late-arriving aircraft). We show each category’s share of total delay minutes.
• Best airline on a route — the carrier with the highest on-time percentage among those with at least 60 flights on that route in the period.

Thresholds and small samples

Percentages computed over a handful of flights are noise, not signal. Route pages require at least 100 flights in the last 12 months to be included in search indexes; airports require 500 departures; flight-number pages require 150 operated flights. Sections whose underlying sample is too small are omitted from a page rather than shown with unreliable numbers, and pages for thin routes carry an explicit caveat.

Update cadence

BTS publishes each month’s data with roughly a two-month lag. We rebuild the entire dataset monthly when new files appear; every page shows the coverage window it was computed from. This site was last updated 2026-07-01.

Known limitations

• Only US domestic flights by US reporting carriers are covered. International flights and foreign airlines are absent.
• Regional carriers (SkyWest, Envoy, Republic, Endeavor…) report under their own names even when flying as American Eagle, Delta Connection, or United Express. Their statistics are shown separately.
• Statistics are historical. They describe what happened over the coverage window and are not a prediction for any specific future flight.
• The most recent ~2 months are always missing due to the reporting lag.

Contact & corrections

Spot a number that looks wrong? See the about page for how to reach the site owner. We treat data integrity bugs as the highest priority issue class.