UA1521
UA1521 (United Airlines) is a multi-stop service on 10 routes, busiest Denver to Cleveland. Of 644 departures recorded from October 2024 to July 2026, 84.1% left on time, according to the US BTS.
- On-time departures84.1%of 644 flights
- Average delay7.8 min
- July 202631▲ 0.0%vs July 2025
- Cancelled0.2%
- Legs flown under this number10
Recorded departures by month
All legs under this number combined; see the leg table.
The most recent periods19 periods
| Period | Departures 2025 | Departures 2026 | Change vs last year |
|---|---|---|---|
| January | 30 | 31 | ▲ 3.3% |
| February | 24 | 28 | ▲ 16.7% |
| March | 28 | 31 | ▲ 10.7% |
| April | 30 | 29 | ▼ 3.3% |
| May | 31 | 31 | 0.0% |
| June | 30 | 30 | 0.0% |
| July | 31 | 31 | 0.0% |
| August | 31 | – | – |
| September | 30 | – | – |
| October | 31 | – | in progress |
| November | 27 | – | – |
| December | 31 | – | – |
| Year to date (Jan–Jul) | 204 | 211 | ▲ 3.4% |
according to the US BTS · October 2024 → July 2026
On-time departures by month
On time = departure within 15 minutes of schedule. Non-cancelled flights with a recorded delay only.
The most recent periods19 periods
| Period | On time 2025 | On time 2026 | Change vs last year |
|---|---|---|---|
| January | 72.4% | 80.7% | ▲ 11.4% |
| February | 70.8% | 85.7% | ▲ 21.0% |
| March | 92.9% | 83.9% | ▼ 9.7% |
| April | 86.7% | 96.6% | ▲ 11.4% |
| May | 77.4% | 90.3% | ▲ 16.7% |
| June | 93.3% | 86.7% | ▼ 7.1% |
| July | 90.3% | 87.1% | ▼ 3.6% |
| August | 83.9% | – | – |
| September | 93.3% | – | – |
| October | 77.4% | – | in progress |
| November | 70.4% | – | – |
| December | 87.1% | – | – |
| Year-to-date average (Jan–Jul) | 83.4% | 87.3% | ▲ 4.6% |
according to the US BTS · October 2024 → July 2026
Average departure delay by month
according to the US BTS · October 2024 → July 2026
Cancelled departures by month
The most recent periods19 periods
| Period | Cancelled 2025 | Cancelled 2026 | Change vs last year |
|---|---|---|---|
| January | 1 | 0 | ▼ 100.0% |
| February | 0 | 0 | – |
| March | 0 | 0 | – |
| April | 0 | 0 | – |
| May | 0 | 0 | – |
| June | 0 | 0 | – |
| July | 0 | 0 | – |
| August | 0 | – | – |
| September | 0 | – | – |
| October | 0 | – | in progress |
| November | 0 | – | – |
| December | 0 | – | – |
| Year to date (Jan–Jul) | 1 | 0 | ▼ 100.0% |
according to the US BTS · October 2024 → July 2026
This is a historical record of departures already flown, not a forecast for your flight.
Several legs: the headline figure averages all of them. See the leg table.
Cancellation share
- Not cancelled 99.8% 643
- Cancelled 0.2% 1
Share of all recorded flights in the period, all legs. · Oct 12, 2024 → Jul 31, 2026
On time, leg by leg
Departures within 15 minutes of schedule; small figure = departures recorded.
Legs flown under this number
4| Routes | Distance (km) | Avg delay | On time | Departures |
|---|---|---|---|---|
| DEN CLE Denver International Airport – Cleveland Hopkins International Airport | 1,928 | 5.6 min | 86.6% | 344 |
| IAD MSY Washington Dulles International Airport – Louis Armstrong New Orleans International Airport | 1,537 | 10.5 min | 78.6% | 84 |
| DSM DEN Des Moines International Airport – Denver International Airport | 947 | 7.8 min | 88.9% | 72 |
| IAH SFO George Bush Intercontinental Airport – San Francisco International Airport | 2,627 | 18.6 min | 71.7% | 61 |
Monthly figures
| Period | Departures | With departure delay recorded | On time | Cancelled |
|---|---|---|---|---|
| October 2024 | 20 | 20 | 95.0% | 0 |
| November 2024 | 30 | 30 | 73.3% | 0 |
| December 2024 | 29 | 29 | 75.9% | 0 |
| January 2025 | 30 | 29 | 72.4% | 1 |
| February 2025 | 24 | 24 | 70.8% | 0 |
| March 2025 | 28 | 28 | 92.9% | 0 |
| April 2025 | 30 | 30 | 86.7% | 0 |
| May 2025 | 31 | 31 | 77.4% | 0 |
| June 2025 | 30 | 30 | 93.3% | 0 |
| July 2025 | 31 | 31 | 90.3% | 0 |
| August 2025 | 31 | 31 | 83.9% | 0 |
| September 2025 | 30 | 30 | 93.3% | 0 |
| October 2025 | 31 | 31 | 77.4% | 0 |
| November 2025 | 27 | 27 | 70.4% | 0 |
| December 2025 | 31 | 31 | 87.1% | 0 |
| January 2026 | 31 | 31 | 80.7% | 0 |
| February 2026 | 28 | 28 | 85.7% | 0 |
| March 2026 | 31 | 31 | 83.9% | 0 |
| April 2026 | 29 | 29 | 96.6% | 0 |
| May 2026 | 31 | 31 | 90.3% | 0 |
| June 2026 | 30 | 30 | 86.7% | 0 |
| July 2026 | 31 | 31 | 87.1% | 0 |