Flight Reliability
F9 3871 · Frontier Airlines
Salt Lake City → Phoenix (SLC–PHX)
- 84%
- Arrive within 15 minutes
- 9 min
- Average arrival delay
- 2.2%
- Cancelled
- 13 min early
- Median arrival delay
Based on 178 historical flights. Data through May 2026.
What the data says
The 12–3 PM departure wins.
F9 3871 departing between 12–3 PM arrived on time 96% of the time, versus 66% between 3–6 PM.
Saturdays have been rough.
F9 3871 arrived on time 94% of the time on Tuesdays and just 70% on Saturdays. That gap is worth planning around.
Better than the Frontier Airlines network average.
F9 3871 arrived on time 84% of the time, versus 73% across the Frontier Airlines network.
Trending in the right direction.
F9 3871 arrived on time 94% of the time over the last three months in the data, compared with 63% in the three months before that.
The breakdown
- Mon72%(29 flights)
- Tue94%(18 flights)
- Wed—(9 flights)
- Thu83%(30 flights)
- Fri91%(34 flights)
- Sat70%(20 flights)
- Sun88%(32 flights)
- 9 AM–12 PM91%(21 flights)
- 12–3 PM96%(76 flights)
- 3–6 PM66%(29 flights)
- 6–9 PM78%(23 flights)
- 9 PM–12 AM70%(23 flights)
Jun 82% → May 93% on time
| Month | On-time percentage | Flights |
|---|---|---|
| June 2025 | 82% | 17 |
| July 2025 | 84% | 19 |
| August 2025 | 67% | 15 |
| October 2025 | 60% | 10 |
| November 2025 | 63% | 16 |
| March 2026 | 100% | 19 |
| April 2026 | 90% | 29 |
| May 2026 | 93% | 30 |
- Departures on time
- 87%
- Diverted
- 1.1%
- Flights flown
- 172
- Months covered
- 10
Same route, other flights
Keep nerding
Based on 178 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.