OO4639
OO4639 (SkyWest Airlines) is a multi-stop service on 21 routes, busiest Ontario to San Francisco. Of 657 departures recorded from October 2024 to July 2026, 74.4% left on time, according to the US BTS.
- On-time departures74.4%of 657 flights
- Average delay24.6 min
- July 202631▲ 0.0%vs July 2025
- Cancelled1.2%
- Legs flown under this number21
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 | 31 | 31 | 0.0% |
| February | 27 | 28 | ▲ 3.7% |
| March | 31 | 31 | 0.0% |
| April | 30 | 30 | 0.0% |
| May | 31 | 31 | 0.0% |
| June | 30 | 30 | 0.0% |
| July | 31 | 31 | 0.0% |
| August | 31 | – | – |
| September | 30 | – | – |
| October | 31 | – | in progress |
| November | 30 | – | – |
| December | 31 | – | – |
| Year to date (Jan–Jul) | 211 | 212 | ▲ 0.5% |
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 | 83.9% | 83.3% | ▼ 0.6% |
| February | 80.8% | 78.6% | ▼ 2.7% |
| March | 73.3% | 90.3% | ▲ 23.2% |
| April | 90.0% | 63.3% | ▼ 29.6% |
| May | 61.3% | 41.9% | ▼ 31.6% |
| June | 63.0% | 72.4% | ▲ 15.0% |
| July | 73.3% | 90.3% | ▲ 23.2% |
| August | 71.0% | – | – |
| September | 76.7% | – | – |
| October | 77.4% | – | in progress |
| November | 73.3% | – | – |
| December | 58.1% | – | – |
| Year-to-date average (Jan–Jul) | 75.1% | 74.3% | ▼ 1.0% |
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 | 0 | 1 | – |
| February | 1 | 0 | ▼ 100.0% |
| March | 1 | 0 | ▼ 100.0% |
| April | 0 | 0 | – |
| May | 0 | 0 | – |
| June | 3 | 1 | ▼ 66.7% |
| July | 1 | 0 | ▼ 100.0% |
| August | 0 | – | – |
| September | 0 | – | – |
| October | 0 | – | in progress |
| November | 0 | – | – |
| December | 0 | – | – |
| Year to date (Jan–Jul) | 6 | 2 | ▼ 66.7% |
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 98.8% 649
- Cancelled 1.2% 8
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
10Monthly figures
| Period | Departures | With departure delay recorded | On time | Cancelled |
|---|---|---|---|---|
| October 2024 | 20 | 20 | 100.0% | 0 |
| November 2024 | 30 | 30 | 76.7% | 0 |
| December 2024 | 31 | 31 | 67.7% | 0 |
| January 2025 | 31 | 31 | 83.9% | 0 |
| February 2025 | 27 | 26 | 80.8% | 1 |
| March 2025 | 31 | 30 | 73.3% | 1 |
| April 2025 | 30 | 30 | 90.0% | 0 |
| May 2025 | 31 | 31 | 61.3% | 0 |
| June 2025 | 30 | 27 | 63.0% | 3 |
| July 2025 | 31 | 30 | 73.3% | 1 |
| August 2025 | 31 | 31 | 71.0% | 0 |
| September 2025 | 30 | 30 | 76.7% | 0 |
| October 2025 | 31 | 31 | 77.4% | 0 |
| November 2025 | 30 | 30 | 73.3% | 0 |
| December 2025 | 31 | 31 | 58.1% | 0 |
| January 2026 | 31 | 30 | 83.3% | 1 |
| February 2026 | 28 | 28 | 78.6% | 0 |
| March 2026 | 31 | 31 | 90.3% | 0 |
| April 2026 | 30 | 30 | 63.3% | 0 |
| May 2026 | 31 | 31 | 41.9% | 0 |
| June 2026 | 30 | 29 | 72.4% | 1 |
| July 2026 | 31 | 31 | 90.3% | 0 |