Flight Reliability
F9 2421 · Frontier Airlines
Denver → San Diego (DEN–SAN)
85
Pretty Reliable
WanderNerd Reliability Score
- 87%
- Arrive within 15 minutes
- 6 min early
- Average arrival delay
- 2.5%
- Cancelled
- 15 min early
- Median arrival delay
Based on 40 historical flights. Data through May 2026.
What the data says
Better than the DEN–SAN route average.
F9 2421 arrived on time 87% of the time, versus 76% across the DEN–SAN route.
Better than the Frontier Airlines network average.
F9 2421 arrived on time 87% of the time, versus 73% across the Frontier Airlines network.
The breakdown
- Mon90%(10 flights)
- Tue—(2 flights)
- Wed—(3 flights)
- Thu—(8 flights)
- Fri—(7 flights)
- Sat—(2 flights)
- Sun—(7 flights)
- 6–9 AM89%(36 flights)
- 12–3 PM—(3 flights)
- Departures on time
- 82%
- Diverted
- 0%
- Flights flown
- 39
- Months covered
- 3
Same route, other flights
Keep nerding
Based on 40 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.