Methodology
Exact definitions, denominators, thresholds and limitations behind every DelayOdds flight reliability report.
What we count
DelayOdds uses the Bureau of Transportation Statistics Reporting Carrier On-Time Performance dataset. The current release window is July 1, 2025 through June 30, 2026. Each row is a scheduled domestic flight reported under federal requirements.
A completed flight arriving less than 15 minutes after its scheduled arrival.
A completed flight arriving 30 minutes or more after schedule.
A flight marked cancelled in the BTS record. It stays in the scheduled-flight denominator.
A flight marked diverted. It also stays in the scheduled-flight denominator.
The denominator matters
Our headline on-time rate is on-time arrivals divided by all scheduled reportable flights—not just completed flights. That prevents cancellations from quietly disappearing from the probability a traveler experienced when choosing a schedule.
Publication thresholds
- Directional route report: at least 240 scheduled flights in twelve months.
- Route × marketing carrier: at least 160 flights.
- Origin airport report: at least 2,000 departures.
- Airport × marketing carrier: at least 600 departures.
- Time-of-day row: at least 40 flights; weekday row: at least 30.
Risk bands
The plain-language band is a deterministic label, not a predictive model. “Lower disruption” requires at least 80% on time and under 1.5% cancelled; “Generally reliable” requires at least 70% on time and under 2.5% cancelled; “Variable” requires at least 58% on time and under 4% cancelled; remaining samples are labeled “Higher disruption.” The percentages and sample always remain visible.
Marketing carrier and codeshares
Airline comparisons use Marketing_Airline_Network. That reflects the brand under which the itinerary is marketed; the operating carrier may differ on a codeshare.
Limitations
- This is a twelve-month historical window, not a live forecast or flight-status service.
- The reporting dataset does not cover every operator or every kind of flight.
- Route mix, schedule time and season can confound airline-wide comparisons.
- Cause minutes apply to qualifying delayed flights and should not be read as probabilities for a future flight.
- Airport pages summarize outcomes for departing reportable flights, not security lines, baggage, gates or all airport operations.