WN4139
WN4139 (Southwest Airlines) is a multi-stop service on 16 routes, busiest Ontario to Oakland. Of 299 departures recorded from October 2024 to July 2026, 83.5% left on time, according to the US BTS.
- On-time departures83.5%of 299 flights
- Average delay8.3 min
- July 202626▼ 3.7%vs July 2025
- Cancelled1.0%
- Legs flown under this number16
Recorded departures by month
All legs under this number combined; see the leg table.
Months without data are left blank.
The most recent periods18 periods
| Period | Departures 2025 | Departures 2026 | Change vs last year |
|---|---|---|---|
| January | – | 8 | – |
| February | 2 | 18 | ▲ 800.0% |
| March | 1 | 2 | ▲ 100.0% |
| April | 23 | 20 | ▼ 13.0% |
| May | 31 | 26 | ▼ 16.1% |
| June | 26 | 21 | ▼ 19.2% |
| July | 27 | 26 | ▼ 3.7% |
| August | 19 | – | – |
| September | 17 | – | – |
| October | 1 | – | in progress |
| November | 15 | – | – |
| December | 6 | – | – |
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 periods18 periods
| Period | On time 2025 | On time 2026 | Change vs last year |
|---|---|---|---|
| January | – | 85.7% | – |
| February | 50.0% | 61.1% | ▲ 22.2% |
| March | 100.0% | 0.0% | ▼ 100.0% |
| April | 95.7% | 100.0% | ▲ 4.5% |
| May | 83.3% | 84.6% | ▲ 1.5% |
| June | 88.5% | 95.2% | ▲ 7.7% |
| July | 88.9% | 88.5% | ▼ 0.5% |
| August | 68.4% | – | – |
| September | 64.7% | – | – |
| October | 0.0% | – | in progress |
| November | 78.6% | – | – |
| December | 83.3% | – | – |
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 periods18 periods
| Period | Cancelled 2025 | Cancelled 2026 | Change vs last year |
|---|---|---|---|
| January | – | 1 | – |
| February | 0 | 0 | – |
| March | 0 | 0 | – |
| April | 0 | 0 | – |
| May | 1 | 0 | ▼ 100.0% |
| June | 0 | 0 | – |
| July | 0 | 0 | – |
| August | 0 | – | – |
| September | 0 | – | – |
| October | 0 | – | in progress |
| November | 1 | – | – |
| 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 99.0% 296
- Cancelled 1.0% 3
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 |
|---|---|---|---|---|
| ONT OAK Ontario International Airport – Oakland San Francisco Bay Airport | 582 | 3.1 min | 88.5% | 52 |
| MSY STL Louis Armstrong New Orleans International Airport – St. Louis Lambert International Airport | 974 | 4.1 min | 87.8% | 50 |
| MCO MCI Orlando International Airport – Kansas City International Airport | 1,726 | -0.6 min | 97.6% | 42 |
| BNA BUR Nashville International Airport – Hollywood Burbank/Bob Hope Airport | 2,875 | 18.5 min | 61.8% | 34 |
Monthly figures
| Period | Departures | With departure delay recorded | On time | Cancelled |
|---|---|---|---|---|
| October 2024 | 9 | 9 | 88.9% | 0 |
| November 2024 | 1 | 1 | 100.0% | 0 |
| February 2025 | 2 | 2 | 50.0% | 0 |
| March 2025 | 1 | 1 | 100.0% | 0 |
| April 2025 | 23 | 23 | 95.7% | 0 |
| May 2025 | 31 | 30 | 83.3% | 1 |
| June 2025 | 26 | 26 | 88.5% | 0 |
| July 2025 | 27 | 27 | 88.9% | 0 |
| August 2025 | 19 | 19 | 68.4% | 0 |
| September 2025 | 17 | 17 | 64.7% | 0 |
| October 2025 | 1 | 1 | 0.0% | 0 |
| November 2025 | 15 | 14 | 78.6% | 1 |
| December 2025 | 6 | 6 | 83.3% | 0 |
| January 2026 | 8 | 7 | 85.7% | 1 |
| February 2026 | 18 | 18 | 61.1% | 0 |
| March 2026 | 2 | 2 | 0.0% | 0 |
| April 2026 | 20 | 20 | 100.0% | 0 |
| May 2026 | 26 | 26 | 84.6% | 0 |
| June 2026 | 21 | 21 | 95.2% | 0 |
| July 2026 | 26 | 26 | 88.5% | 0 |