Carrier route record

F9SFO→LAX

Frontier Airlines · San Francisco to Los Angeles

Flights: 394
Period: September 2025 to August 2026
Share of route: 3%
Carriers: 8

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

Frontier on SFO to LAX draws a C. About one flight in three arrives at least 15 minutes late, and the typical late arrival is a little over an hour behind schedule. Build slack into anything you connect to. That rests on 394 flights. The strongest carrier on the route with a full sample, United Airlines, flew 3,335 at 77.7% on time.

United Airlines is the most reliable of the five carriers covered here at 77.7% on time across 3,335 flights.

On time

66.5%

Arrivals under 15 minutes late, of 388 completed flights

Avg delay

77 min

Across delayed arrivals only, not all flights

Cancelled

1.52%

National rate is 1.89%

Whole route

70.9%

Every carrier on SFO to LAX, 11,437 flights

These figures cover 394 flights between September 2025 and August 2026. Beyond the headline rate, 13.7% of arrivals land a full hour or more behind schedule, against 8.3% nationally.

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Carrier by carrier

Frontier against every carrier on SFO to LAX

Frontier flew 394 of the 11,437 flights on SFO to LAX, about 3% of it. Its 66.5% on time is 4 points worse than the route as a whole, which runs 70.9%. Ranked by on-time rate it is number five of eight carriers on the route, where the range runs from United at 77.7% to Envoy at 0.0%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The choice of carrier is not cosmetic here. United Airlines arrives on time 77.7% of the time; Southwest Airlines manages 56.7%. Sample sizes sit next to every figure, because a two-point gap across 1,472 flights means less than a ten-point one.

On-time performance by carrier on SFO to LAX
Airline	Flights	On time	Avg delay	Cancelled	Grade
United Airlines	3,335	77.7%	46 min	0.15%	B+
American Airlinesthin sample	303	76.2%	100 min	0.00%	B+
SkyWest Airlines	2,513	72.9%	61 min	1.07%	C
Delta Air Lines	2,373	69.8%	63 min	1.56%	C
Frontier Airlines (this page)	394	66.5%	77 min	1.52%	C
Alaska Airlines	1,046	66.4%	47 min	0.86%	C+
Southwest Airlines	1,472	56.7%	62 min	0.68%	D+
Envoy Airthin sample	1	0.0%	35 min	0.00%	F+

The spread between United and Southwest is 21 points, wide enough that it should decide the booking. On a hundred trips that is 21 more arrivals inside the on-time window.

Flight by flight

Frontier flight numbers on SFO to LAX

F9 285820:2364.6% · 265 flights

Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.

Departure window

When Frontier runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 32 points, against 21 points between the best and worst carrier.

5am–8am5 flights—
8am–11am34 flights84.8%
11am–2pm45 flights53.3%
2pm–5pm53 flights73.6%
5pm–8pm88 flights73.6%
8pm–5am169 flights59.4%

Scale runs 45% to 90%. Rows with fewer than 30 flights show a dash.

The weak window here is the middle of the day, not the evening: 11am–2pm runs 53.3% on time against 84.8% for 8am–11am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 8pm–5am window is the busiest, with 169 flights scheduled in it.

Across the year

Frontier on SFO to LAX through the year

Darker means more delays. Figures are on-time percentages.April best, August worst

August is the worst month at 41.9% on time, 41 points below April, the best at 83.3%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. October was the busiest month here, with 48 flights.

Across the week, Tuesday is the strongest day at 84.2% on time and Friday the weakest at 57.6%, a spread of 27 points.

Arrival by arrival

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

The 130 late arrivals split 31 under half an hour, 46 between 30 and 60 minutes, and 53 an hour or more.

15+ min early91 flights23.5%
Within 15 min167 flights43.0%
15–29 min late31 flights8.0%
30–59 min late46 flights11.9%
1–2 hours late35 flights9.0%
2+ hours late18 flights4.6%

Scale runs 0% to 100%.

Share of 388 completed flights by arrival against schedule.

19 of 132 late departures made up the time and arrived on time, 14% of them. 17 flights left on time and still arrived late.

The worst days

Worst days for Frontier on SFO to LAX

The latest arrival of the period was on 15 January 2026, 15 hours 13 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 November 2025.

The latest arrivals of Frontier on SFO to LAX in the period
Date	Arrived late by	Largest filed cause
15 January 2026	15 hours 13 minutes	Carrier
26 November 2025	11 hours 23 minutes	Late-arriving aircraft
15 September 2025	5 hours 51 minutes	Late-arriving aircraft
5 November 2025	4 hours 57 minutes	Late-arriving aircraft
3 November 2025	4 hours 35 minutes	Late-arriving aircraft

Delay causes

Why Frontier runs late on this route

Late-arriving aircraft accounts for 68% of the 9,956 delay minutes carriers reported here, and the remaining four split what is left.

Late-arriving aircraft
68%
Carrier
24%
National Airspace System
8%

68% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 9,956 reported delay minutes here, that single category outweighs weather by 68 to one. The split is drawn from 9,956 reported delay minutes.

The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 84.8% on time here.

Cancellations sit at 1.52% against a national 1.89%, which is ordinary. Diversions add another 0.00%.

Connections and stage length

What a delay here costs

13.7% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.

At 337 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 8am–11am window matters as much as it does.

The return leg is a different operation and performs like one: it runs 47.7% on time across 395 flights, 19 points below 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 19 points of difference.

One caution: this is a thin sample. 394 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 SFO to LAX

Put together: treat all of this as provisional. 394 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 66.5% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 388 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