Route profile
DEN→BUF
Flight reliability, delays and best times to fly from Denver to Buffalo. · 1,359 miles
Right now
Current conditions at both ends of this route.
Aviation weather is not currently a factor. FAA operational data — ground stops, ground delay programs and closures — is not currently available to FlyerIntel.
Aviation weather is not currently a factor. FAA operational data — ground stops, ground delay programs and closures — is not currently available to FlyerIntel.
Airport conditions describe the airfield, not any individual flight. An airport operating normally is not a guarantee that a specific flight will depart on time.
Route reliability
July 2023 – June 2026
Better than 4% of comparable major US routes (4,577 compared)
Calculated from 1,456 flights. How this is calculated
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – June 2026
Best time to fly
On-time arrival rate by scheduled local departure time.
DEN → BUF flights departing 9 AM–12 PM arrived on time 78.3% of the time, against 48.7% for 6–9 PM departures — a gap of 29.5 percentage points.
By departure window
By departure hour
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – June 2026 · Buckets with fewer than 120 flights are not scored.
Airlines on this route
Performance by the carrier that actually operated the flight.
| Carrier | Flights | On time | Cancelled | Median delay | Severe |
|---|---|---|---|---|---|
| Southwest Airlines | 921 | 56.1% | 0.65% | 10 min | 12.9% |
| United Airlines | 334 | 67.1% | 0.00% | 0 min | 16.2% |
| Frontier Airlines | 201 | 73.5% | 0.50% | -3 min | 6.5% |
Frontier Airlines arrived on time 17.4 percentage points more often than Southwest Airlines on this route.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – June 2026 · Carriers with fewer than 200 flights on this route are not listed.
Weekly and seasonal patterns
By day of week
Saturday is historically the most reliable day and Thursday the least, a gap of 15.0 percentage points.
Historical trend
On-time arrival rate by month.
Over the most recent 12 months (2025-07 to 2026-06), on-time arrivals averaged 66.8% against 61.9% in the 12 months before — improving by 4.9 percentage points.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – June 2026
Data and methodology
All figures on this page are calculated by FlyerIntel from 1,456 DEN → BUF flight records published by the US DOT Bureau of Transportation Statistics, covering July 2023 – June 2026. A flight is counted as delayed when it arrives 15 or more minutes after its scheduled arrival time, following BTS methodology. Cancelled and diverted flights have no arrival time and are excluded from on-time rates rather than counted as late.