Flight Reliability
NK 421 · Spirit Airlines
Houston → Detroit (IAH–DTW)
69
Usually Fine
WanderNerd Reliability Score
- 73%
- Arrive within 15 minutes
- 10 min
- Average arrival delay
- 3.2%
- Cancelled
- 1 min
- Median arrival delay
Based on 31 historical flights. Data through May 2026.
What the data says
Lagging the IAH–DTW route.
NK 421 arrived on time 73% of the time, versus 81% across the IAH–DTW route.
The breakdown
- Mon—(5 flights)
- Tue—(5 flights)
- Wed—(5 flights)
- Thu—(4 flights)
- Fri—(3 flights)
- Sat—(4 flights)
- Sun—(4 flights)
- 3–6 AM72%(18 flights)
- 6–9 AM75%(12 flights)
- Departures on time
- 80%
- Diverted
- 0%
- Flights flown
- 30
- Months covered
- 2
Same route, other flights
Keep nerding
Based on 31 historical flights, because apparently we checked. Historical flight data: U.S. Bureau of Transportation Statistics, June 2025 – May 2026. Data through May 2026. How we calculate this.