Denver (DEN) to Buffalo (BUF) flights
Southwest Airlines, United Airlines fly nonstop from Denver International Airport to Buffalo Niagara International Airport, with about 16 flights a week in July 2026. The 1,359-mile flight takes about 3h 6m gate to gate.
- Distance
- 1,359 mi · 2,187 km
- Flight time
- 3h 6m
- Airlines
- 2
- Seats filled
- 82%
Airlines flying DEN to BUF
| Airline | Flights a week | Aircraft | Passengers (12 months) | Flight time |
|---|---|---|---|---|
| Southwest Airlines | 9 | Boeing 737 MAX 8, Boeing 737-800, Boeing 737-700 / MAX 7 | 37,642 | 3h 1m |
| United Airlines | 7 | Boeing 737-800, Boeing 737 MAX 9, Boeing 737-900ER | 38,760 | 3h 11m |
| Frontier AirlinesSeasonal or ended | n/a | Airbus A321, Airbus A320neo | 6,574 | 3h 3m |
Airlines are the operating carrier: regional airlines such as SkyWest or Horizon often fly under a larger airline's brand.
DEN to BUF flight schedule
6 flight numbers flew this route in August 2026, 1 of them almost daily. The first usually leaves at 10:45am and the last at 5:35pm. Times are local and can change; check with the airline before you book.
| Flight | Departs | Arrives | Days flown in August 2026 | On time (12 months) |
|---|---|---|---|---|
| WN 3510Southwest Airlines | 10:45am | 3:50pm | 4 | n/a |
| WN 3306Southwest Airlines | 11:10am | 4:15pm | 4 | n/a |
| WN 398Southwest Airlines | 1:40pm | 6:45pm | 8 | n/a |
| WN 626Southwest Airlines | 4:05pm | 9:10pm | 12 | 50% |
| UA 248United Airlines | 5:25pm | 10:37pm | 31 | 56% |
| WN 3371Southwest Airlines | 5:35pm | 10:45pm | 4 | n/a |
Is DEN to BUF on time?
From September 2025 to August 2026, 68% of 574 flights arrived within 15 minutes of schedule and 0.2% were cancelled. Flights leaving around 10am were the most punctual (88%), those around 12pm the least (55%). Most delay time was caused by late-arriving aircraft (52%).
| Airline | Flights | On time | Average delay | Cancelled |
|---|---|---|---|---|
| United Airlines | 294 | 71% | 24 min | 0% |
| Southwest Airlines | 258 | 62% | 19 min | 0.4% |
| Frontier Airlines | 22 | 82% | 9 min | 0% |
Airlines as sold: flights operated by regional partners count under the airline on the ticket. Average delay is across all completed flights, early arrivals counted as zero.
On-time arrivals by departure time
| Scheduled departure | Flights | On time, relative | On time |
|---|---|---|---|
| 9am to 10am | 21 | 86% | |
| 10am to 11am | 33 | 88% | |
| 11am to 12pm | 44 | 77% | |
| 12pm to 1pm | 44 | 55% | |
| 1pm to 2pm | 25 | 64% | |
| 4pm to 5pm | 27 | 58% | |
| 5pm to 6pm | 334 | 69% | |
| 7pm to 8pm | 26 | 31% | |
| 8pm to 9pm | 13 | 54% |
Flights by month
| Month | Flights | Flights, relative | Passengers |
|---|---|---|---|
| August 2025 | 80 | 12,474 | |
| September 2025 | 77 | 11,155 | |
| October 2025 | 70 | 10,646 | |
| November 2025 | 52 | 6,580 | |
| December 2025 | 20 | 2,785 | |
| January 2026 | 14 | 1,795 | |
| February 2026 | 37 | 4,116 | |
| March 2026 | 33 | 4,247 | |
| April 2026 | 33 | 4,289 | |
| May 2026 | 36 | 4,699 | |
| June 2026 | 65 | 9,567 | |
| July 2026 | 70 | 10,623 |
Related
Source: US Department of Transportation, T-100 Segment data, August 2025 to July 2026.