About 1 in 8 F9 4129 flights from Salt Lake City arrived 15+ minutes late, diverted or cancelled over the past year (12%); 2.5% were cancelled. The typical flight landed 19 minutes early.
F9 4129: SLC → LAX
Scheduled to leave Salt Lake City at 10:20 a.m. local time. Over the past year it arrived on time 88% of the time (196 flights), worse than other F9 flights on the route at that hour (91%). Last seen in the data Aug 31, 2026.
Usually Frontier Airlines's last flight of the day from Salt Lake City to Los Angeles (57% of days). Frontier Airlines's last SLC–LAX flight was cancelled 2.9% of the time, against 0.0% for its earlier ones. If it's cancelled, the next Frontier Airlines flight is usually around 10:20 a.m. the next morning.
Month by month
By day of week
| Day | Flights | On time |
|---|---|---|
| Monday | 35 | 86% |
| Tuesday | 18 | — |
| Wednesday | 18 | — |
| Thursday | 33 | 85% |
| Friday | 34 | 88% |
| Saturday | 24 | 92% |
| Sunday | 34 | 82% |
Why it was late
All flights SLC → LAX · Connecting off F9 4129? Check the risk
Questions
How often is F9 4129 from SLC to LAX late?
Frontier Airlines 4129 from Salt Lake City, UT to Los Angeles, CA arrived 15 or more minutes late, was diverted or was cancelled on 12% of 196 scheduled flights between September 2025 and August 2026. 2.5% were cancelled.
Flight numbers change. Figures cover flights with this airline, number and route only. "Likely range" is the 95% interval for the true on-time rate given the number of flights. This is history, not live status: check Frontier Airlines for today's flight. Method.