Carrier route record

F9LAX→SLC

Frontier Airlines · Los Angeles to Salt Lake City

Flights: 475
Period: September 2025 to August 2026
Share of route: 11%
Carriers: 6

Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Frontier Airlines.

Frontier on LAX to SLC earns an A. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 8 points better than the national rate of 77.3%. When something does go wrong the average delay runs a little over an hour. That rests on 475 flights. The strongest carrier on the route with a full sample, Delta Air Lines, flew 2,457 at 88.4% on time.

Delta Air Lines is the most reliable of the three carriers covered here at 88.4% on time across 2,457 flights.

On time

85.3%

Arrivals under 15 minutes late, of 469 completed flights

Avg delay

75 min

Across delayed arrivals only, not all flights

Cancelled

1.26%

National rate is 1.89%

Whole route

87.2%

Every carrier on LAX to SLC, 4,195 flights

These figures cover 475 flights between September 2025 and August 2026. The median arrival is 9 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.

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Carrier by carrier

Frontier against every carrier on LAX to SLC

Frontier flew 475 of the 4,195 flights on LAX to SLC, about 11% of it. Its 85.3% on time is 2 points worse than the route as a whole, which runs 87.2%. Ranked by on-time rate it is number five of six carriers on the route, where the range runs from Spirit at 90.9% to Southwest at 79.7%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 88.4% of the time; Southwest Airlines manages 79.7%. Sample sizes sit next to every figure, because a two-point gap across 371 flights means less than a ten-point one.

On-time performance by carrier on LAX to SLC
Airline	Flights	On time	Avg delay	Cancelled	Grade
Spirit Airlinesthin sample	23	90.9%	29 min	4.35%	A−
United Airlinesthin sample	149	88.6%	65 min	0.00%	A+
Delta Air Lines	2,457	88.4%	80 min	0.53%	A+
SkyWest Airlines	720	88.0%	69 min	0.00%	A+
Frontier Airlines (this page)	475	85.3%	75 min	1.26%	A
Southwest Airlines	371	79.7%	47 min	0.27%	B+

Delta leads Southwest by 9 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.

Flight by flight

Frontier flight numbers on LAX to SLC

F9 126810:1082.1% · 256 flights

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Departure window

When Frontier runs best on this route

Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 475 flights.

5am–8am—
8am–11am163 flights86.3%
11am–2pm132 flights86.4%
2pm–5pm62 flights83.9%
5pm–8pm118 flights83.3%
8pm–5am—

Scale runs 75% to 90%. Rows with fewer than 30 flights show a dash.

The time of day barely matters here. The 11am–2pm window tops the set at 86.4% and 5pm–8pm sits at 83.3%, 3 points apart across 475 flights. Pick the departure that suits the trip: whatever is going wrong here is not accumulating over the course of the day. The 8am–11am window is the busiest, with 163 flights scheduled in it.

Across the year

Frontier on LAX to SLC through the year

Darker means more delays. Figures are on-time percentages.November best, September worst

November is the best month on the calendar at 92.7% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. March was the busiest month here, with 60 flights.

Across the week, Tuesday is the strongest day at 95.7% on time and Friday the weakest at 80.0%, a spread of 16 points.

Arrival by arrival

How late Frontier on LAX to SLC runs when it is late

Frontier on LAX to SLC often beats the schedule: 156 of 469 completed flights, 33%, arrived 15 minutes or more early. The 69 late arrivals split 22 under half an hour, 24 between 30 and 60 minutes, and 23 an hour or more.

15+ min early156 flights33.3%
Within 15 min244 flights52.0%
15–29 min late22 flights4.7%
30–59 min late24 flights5.1%
1–2 hours late13 flights2.8%
2+ hours late10 flights2.1%

Scale runs 0% to 100%.

Share of 469 completed flights by arrival against schedule.

Time lost at the gate mostly stays lost. Of 62 departures that left 15 minutes late or more, only 7 made it up before arrival. 14 flights left on time and still arrived late.

The worst days

Worst days for Frontier on LAX to SLC

The latest arrival of the period was on 18 February 2026, 17 hours 52 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). Three of the five worst days fell in March 2026.

The latest arrivals of Frontier on LAX to SLC in the period
Date	Arrived late by	Largest filed cause
18 February 2026	17 hours 52 minutes	Carrier
23 March 2026	3 hours 30 minutes	Late-arriving aircraft
29 April 2026	3 hours 17 minutes	Late-arriving aircraft
8 March 2026	2 hours 55 minutes	Late-arriving aircraft
8 March 2026	2 hours 48 minutes	Late-arriving aircraft

Delay causes

Why Frontier runs late on this route

Late-arriving aircraft accounts for 55% of the 5,181 delay minutes carriers reported here, and the remaining four split what is left.

Late-arriving aircraft
55%
Carrier
32%
National Airspace System
13%
Extreme weather
0%

55% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 5,181 reported delay minutes here, that single category outweighs weather by 55 to one. The split is drawn from 5,181 reported delay minutes.

Cancellations sit at 1.26% against a national 1.89%, which is ordinary. Diversions add another 0.00%.

Connections and stage length

What a delay here costs

Badly late arrivals are rare here: only 4.9% land an hour or more behind schedule, against 8.3% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.

The 590 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty.

The return leg is a different operation and performs like one: it runs 90.0% on time across 475 flights, 5 points above this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 5 points of difference.

One caution: this is a thin sample. 475 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.

What to do with this

Booking Frontier on LAX to SLC

Put together: treat all of this as provisional. 475 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 85.3% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 469 completed flights over 12 months sit behind that.

Where to go next

Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated 22 October 2026; recomputed monthly. How this data is collected.

Key figures