UA2851
UA2851 (United Airlines) is a multi-stop service on 18 routes, busiest San Francisco to Boston. Of 448 departures recorded from October 2024 to July 2026, 88.3% left on time, according to the US BTS.
- On-time departures88.3%of 448 flights
- Average delay3.6 min
- July 202629
- Cancelled0.9%
- Legs flown under this number18
Recorded departures by month
All legs under this number combined; see the leg table.
Months without data are left blank.
The most recent periods16 periods
| Period | Departures 2025 | Departures 2026 | Change vs last year |
|---|---|---|---|
| January | 50 | 26 | ▼ 48.0% |
| February | 40 | 28 | ▼ 30.0% |
| March | 5 | 4 | ▼ 20.0% |
| April | – | 1 | – |
| May | 21 | 26 | ▲ 23.8% |
| June | – | 29 | – |
| July | – | 29 | – |
| August | 13 | – | – |
| September | 30 | – | – |
| October | 31 | – | in progress |
| November | 30 | – | – |
| December | 17 | – | – |
according to the US BTS · October 2024 → July 2026
On-time departures by month
Months without data are left blank.
On time = departure within 15 minutes of schedule. Non-cancelled flights with a recorded delay only.
The most recent periods16 periods
| Period | On time 2025 | On time 2026 | Change vs last year |
|---|---|---|---|
| January | 95.8% | 83.3% | ▼ 13.0% |
| February | 77.5% | 92.9% | ▲ 19.8% |
| March | 60.0% | 100.0% | ▲ 66.7% |
| April | – | 100.0% | – |
| May | 100.0% | 69.2% | ▼ 30.8% |
| June | – | 89.7% | – |
| July | – | 79.3% | – |
| August | 84.6% | – | – |
| September | 93.3% | – | – |
| October | 96.8% | – | in progress |
| November | 93.3% | – | – |
| December | 94.1% | – | – |
according to the US BTS · October 2024 → July 2026
Average departure delay by month
Months without data are left blank.
according to the US BTS · October 2024 → July 2026
Cancelled departures by month
Months without data are left blank.
The most recent periods16 periods
| Period | Cancelled 2025 | Cancelled 2026 | Change vs last year |
|---|---|---|---|
| January | 2 | 2 | 0.0% |
| February | 0 | 0 | – |
| March | 0 | 0 | – |
| April | – | 0 | – |
| May | 0 | 0 | – |
| June | – | 0 | – |
| July | – | 0 | – |
| August | 0 | – | – |
| September | 0 | – | – |
| October | 0 | – | in progress |
| November | 0 | – | – |
| December | 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 99.1% 444
- Cancelled 0.9% 4
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
7| Routes | Distance (km) | Avg delay | On time | Departures |
|---|---|---|---|---|
| SFO BOS San Francisco International Airport – Boston Logan International Airport | 4,341 | 6.2 min | 89.7% | 58 |
| SFO CLE San Francisco International Airport – Cleveland Hopkins International Airport | 3,470 | -3.4 min | 94.3% | 53 |
| ORD IAH Chicago O'Hare International Airport – George Bush Intercontinental Airport | 1,491 | 4.7 min | 91.9% | 37 |
| MIA EWR Miami International Airport – Newark Liberty International Airport | 1,750 | 1.7 min | 85.7% | 37 |
| IAH SNA George Bush Intercontinental Airport – John Wayne Orange County International Airport | 2,163 | 1.2 min | 89.2% | 37 |
| BUR SFO Hollywood Burbank/Bob Hope Airport – San Francisco International Airport | 525 | 4.0 min | 80.0% | 37 |
| FLL EWR Fort Lauderdale Hollywood International Airport – Newark Liberty International Airport | 1,717 | -5.5 min | 96.7% | 30 |
Monthly figures
| Period | Departures | With departure delay recorded | On time | Cancelled |
|---|---|---|---|---|
| October 2024 | 20 | 20 | 95.0% | 0 |
| November 2024 | 30 | 30 | 90.0% | 0 |
| December 2024 | 18 | 18 | 77.8% | 0 |
| January 2025 | 50 | 48 | 95.8% | 2 |
| February 2025 | 40 | 40 | 77.5% | 0 |
| March 2025 | 5 | 5 | 60.0% | 0 |
| May 2025 | 21 | 21 | 100.0% | 0 |
| August 2025 | 13 | 13 | 84.6% | 0 |
| September 2025 | 30 | 30 | 93.3% | 0 |
| October 2025 | 31 | 31 | 96.8% | 0 |
| November 2025 | 30 | 30 | 93.3% | 0 |
| December 2025 | 17 | 17 | 94.1% | 0 |
| January 2026 | 26 | 24 | 83.3% | 2 |
| February 2026 | 28 | 28 | 92.9% | 0 |
| March 2026 | 4 | 4 | 100.0% | 0 |
| April 2026 | 1 | 1 | 100.0% | 0 |
| May 2026 | 26 | 26 | 69.2% | 0 |
| June 2026 | 29 | 29 | 89.7% | 0 |
| July 2026 | 29 | 29 | 79.3% | 0 |