WN421
WN421 (Southwest Airlines) is a multi-stop service on 29 routes, busiest Little Rock to St Louis. Of 653 departures recorded from October 2024 to July 2026, 84.6% left on time, according to the US BTS.
- On-time departures84.6%of 653 flights
- Average delay5.8 min
- July 202627▲ 35.0%vs July 2025
- Cancelled0.5%
- Legs flown under this number29
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 | 33 | 30 | ▼ 9.1% |
| February | 28 | 28 | 0.0% |
| March | 67 | 31 | ▼ 53.7% |
| April | 23 | 38 | ▲ 65.2% |
| May | 8 | 39 | ▲ 387.5% |
| June | 21 | 28 | ▲ 33.3% |
| July | 20 | 27 | ▲ 35.0% |
| August | 31 | – | – |
| September | 30 | – | – |
| October | 31 | – | in progress |
| November | 21 | – | – |
| December | 27 | – | – |
| Year to date (Jan–Jul) | 200 | 221 | ▲ 10.5% |
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 | 93.6% | 93.3% | ▼ 0.2% |
| February | 96.3% | 64.3% | ▼ 33.2% |
| March | 94.0% | 93.6% | ▼ 0.5% |
| April | 78.3% | 97.4% | ▲ 24.4% |
| May | 62.5% | 92.3% | ▲ 47.7% |
| June | 95.2% | 67.9% | ▼ 28.7% |
| July | 90.0% | 59.3% | ▼ 34.2% |
| August | 83.9% | – | – |
| September | 50.0% | – | – |
| October | 77.4% | – | in progress |
| November | 85.7% | – | – |
| December | 74.1% | – | – |
| Year-to-date average (Jan–Jul) | 87.1% | 81.1% | ▼ 6.9% |
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 | 2 | 0 | ▼ 100.0% |
| February | 1 | 0 | ▼ 100.0% |
| 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) | 3 | 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 99.5% 650
- Cancelled 0.5% 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
6| Routes | Distance (km) | Avg delay | On time | Departures |
|---|---|---|---|---|
| LIT STL Bill & Hillary Clinton National Airport/Adams Field – St. Louis Lambert International Airport | 477 | -1.3 min | 95.0% | 123 |
| SFO AUS San Francisco International Airport – Austin Bergstrom International Airport | 2,417 | 15.7 min | 63.8% | 58 |
| COS DEN City of Colorado Springs Municipal Airport – Denver International Airport | 117 | 7.0 min | 81.0% | 58 |
| AUS PHX Austin Bergstrom International Airport – Phoenix Sky Harbor International Airport | 1,401 | 1.7 min | 91.4% | 58 |
| STL SAV St. Louis Lambert International Airport – Savannah Hilton Head International Airport | 1,109 | -1.3 min | 93.2% | 44 |
| DEN STL Denver International Airport – St. Louis Lambert International Airport | 1,236 | -2.9 min | 100.0% | 33 |
Monthly figures
| Period | Departures | With departure delay recorded | On time | Cancelled |
|---|---|---|---|---|
| October 2024 | 20 | 20 | 100.0% | 0 |
| November 2024 | 32 | 32 | 96.9% | 0 |
| December 2024 | 40 | 40 | 85.0% | 0 |
| January 2025 | 33 | 31 | 93.6% | 2 |
| February 2025 | 28 | 27 | 96.3% | 1 |
| March 2025 | 67 | 67 | 94.0% | 0 |
| April 2025 | 23 | 23 | 78.3% | 0 |
| May 2025 | 8 | 8 | 62.5% | 0 |
| June 2025 | 21 | 21 | 95.2% | 0 |
| July 2025 | 20 | 20 | 90.0% | 0 |
| August 2025 | 31 | 31 | 83.9% | 0 |
| September 2025 | 30 | 30 | 50.0% | 0 |
| October 2025 | 31 | 31 | 77.4% | 0 |
| November 2025 | 21 | 21 | 85.7% | 0 |
| December 2025 | 27 | 27 | 74.1% | 0 |
| January 2026 | 30 | 30 | 93.3% | 0 |
| February 2026 | 28 | 28 | 64.3% | 0 |
| March 2026 | 31 | 31 | 93.6% | 0 |
| April 2026 | 38 | 38 | 97.4% | 0 |
| May 2026 | 39 | 39 | 92.3% | 0 |
| June 2026 | 28 | 28 | 67.9% | 0 |
| July 2026 | 27 | 27 | 59.3% | 0 |