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Flight Reliability

F9 4129 · Frontier Airlines

Salt Lake City → Los Angeles (SLC–LAX)

84
Pretty Reliable
WanderNerd Reliability Score
90%
Arrive within 15 minutes
7 min early
Average arrival delay
3.4%
Cancelled
18 min early
Median arrival delay

Based on 118 historical flights. Data through May 2026.

What the data says

3–6 PM has a slight edge.

Departures between 3–6 PM arrived on time 91% of the time, against 85% between 6–9 PM.

Friday comes out ahead.

A small edge: 91% on time on Fridays against 85% on Thursdays.

Well ahead of the Frontier Airlines network.

F9 4129 arrived on time 90% of the time, versus 73% across the Frontier Airlines network.

Keep a backup plan handy.

F9 4129 was cancelled 3.4% of the time. Typical for U.S. flights is around 1–2%.

The breakdown

On-time by weekday
  • Mon86%(22 flights)
  • Tue—(8 flights)
  • Wed—(8 flights)
  • Thu85%(20 flights)
  • Fri91%(21 flights)
  • Sat86%(14 flights)
  • Sun91%(21 flights)
On-time by departure window
  • 12–3 PM89%(26 flights)
  • 3–6 PM91%(75 flights)
  • 6–9 PM85%(13 flights)
On-time trend by month
85%
Apr

Nov 100% → Apr 85% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
November 2025100%11
December 202593%14
January 202681%16
February 202695%19
March 202689%28
April 202685%13
Departures on time
86%
Diverted
0%
Flights flown
114
Months covered
8

Same route, other flights

Keep nerding

Based on 118 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.