NK421
NK421 (Spirit Airlines) is a multi-stop service on 3 routes, busiest Los Angeles to Houston. Of 127 departures recorded from October 2024 to December 2025, 86.5% left on time, according to the US BTS.
- On-time departures86.5%of 127 flights
- Average delay3.0 min
- December 20253▼ 90.0%vs December 2024
- Cancelled0.8%
- Legs flown under this number3
Recorded departures by month
Short series — NK421 has only 8 months so far. Enough to show the level now, not enough to read a trend.
All legs under this number combined; see the leg table.
Months without data are left blank.
The most recent periods8 periods
| Period | Departures 2024 | Departures 2025 | Change vs last year |
|---|---|---|---|
| January | – | 8 | – |
| February | – | – | – |
| March | – | – | – |
| April | – | 6 | – |
| May | – | 2 | – |
| June | – | – | – |
| July | – | – | – |
| August | – | – | – |
| September | – | – | – |
| October | 20 | – | – |
| November | 30 | 28 | ▼ 6.7% |
| December | 30 | 3 | ▼ 90.0% |
according to the US BTS · October 2024 → December 2025
On-time departures by month
Short series — NK421 has only 8 months so far. Enough to show the level now, not enough to read a trend.
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 periods8 periods
| Period | On time 2024 | On time 2025 | Change vs last year |
|---|---|---|---|
| January | – | 62.5% | – |
| February | – | – | – |
| March | – | – | – |
| April | – | 100.0% | – |
| May | – | 100.0% | – |
| June | – | – | – |
| July | – | – | – |
| August | – | – | – |
| September | – | – | – |
| October | 90.0% | – | – |
| November | 93.3% | 77.8% | ▼ 16.7% |
| December | 86.7% | 100.0% | ▲ 15.4% |
according to the US BTS · October 2024 → December 2025
Average departure delay by month
Short series — NK421 has only 8 months so far. Enough to show the level now, not enough to read a trend.
Months without data are left blank.
according to the US BTS · October 2024 → December 2025
Cancelled departures by month
Short series — NK421 has only 8 months so far. Enough to show the level now, not enough to read a trend.
Months without data are left blank.
The most recent periods8 periods
| Period | Cancelled 2024 | Cancelled 2025 | Change vs last year |
|---|---|---|---|
| January | – | 0 | – |
| February | – | – | – |
| March | – | – | – |
| April | – | 0 | – |
| May | – | 0 | – |
| June | – | – | – |
| July | – | – | – |
| August | – | – | – |
| September | – | – | – |
| October | 0 | – | – |
| November | 0 | 1 | – |
| December | 0 | 0 | – |
according to the US BTS · October 2024 → December 2025
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 99.2% 126
- Cancelled 0.8% 1
Share of all recorded flights in the period, all legs. · Oct 12, 2024 → Dec 3, 2025
On time, leg by leg
Departures within 15 minutes of schedule; small figure = departures recorded.
Legs flown under this number
2| Routes | Distance (km) | Avg delay | On time | Departures |
|---|---|---|---|---|
| LAX IAH Los Angeles International Airport – George Bush Intercontinental Airport | 2,215 | 2.3 min | 87.5% | 88 |
| IAH DTW George Bush Intercontinental Airport – Detroit Metropolitan Wayne County Airport | 1,731 | 6.9 min | 80.0% | 31 |
Monthly figures
| Period | Departures | With departure delay recorded | On time | Cancelled |
|---|---|---|---|---|
| October 2024 | 20 | 20 | 90.0% | 0 |
| November 2024 | 30 | 30 | 93.3% | 0 |
| December 2024 | 30 | 30 | 86.7% | 0 |
| January 2025 | 8 | 8 | 62.5% | 0 |
| April 2025 | 6 | 6 | 100.0% | 0 |
| May 2025 | 2 | 2 | 100.0% | 0 |
| November 2025 | 28 | 27 | 77.8% | 1 |
| December 2025 | 3 | 3 | 100.0% | 0 |