Carrier route record

F9LAX→SJC

Frontier Airlines · Los Angeles to San Jose

Flights: 138
Period: September 2025 to August 2026
Share of route: 3%
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 SJC lands a B−, 3 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about 50 minutes on average. That rests on 138 flights. The strongest carrier on the route with a full sample, SkyWest Airlines, flew 1,805 at 90.7% on time.

SkyWest Airlines is the most reliable of the three carriers covered here at 90.7% on time across 1,805 flights.

On time

80.5%

Arrivals under 15 minutes late, of 133 completed flights

Avg delay

50 min

Across delayed arrivals only, not all flights

Cancelled

3.62%

National rate is 1.89%

Whole route

85.6%

Every carrier on LAX to SJC, 4,471 flights

These figures cover 138 flights between September 2025 and August 2026. The median arrival is 7 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 SJC

Frontier flew 138 of the 4,471 flights on LAX to SJC, about 3% of it. Its 80.5% on time is 5 points worse than the route as a whole, which runs 85.6%. Ranked by on-time rate it is number five of six carriers on the route, where the range runs from United at 100.0% to American at 66.7%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 90.7% of the time; Southwest Airlines manages 80.6%. Sample sizes sit next to every figure, because a two-point gap across 1,871 flights means less than a ten-point one.

On-time performance by carrier on LAX to SJC
Airline	Flights	On time	Avg delay	Cancelled	Grade
United Airlinesthin sample	1	100.0%	—	0.00%	A+
SkyWest Airlines	1,805	90.7%	58 min	0.39%	A+
Delta Air Lines	650	86.9%	59 min	2.15%	A
Southwest Airlines	1,871	80.6%	50 min	0.91%	B+
Frontier Airlines (this page)thin sample	138	80.5%	50 min	3.62%	B−
American Airlinesthin sample	6	66.7%	39 min	0.00%	C+

SkyWest leads Southwest by 10 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.

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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 138 flights.

5am–8am—
8am–11am49 flights85.4%
11am–2pm10 flights—
2pm–5pm—
5pm–8pm79 flights78.7%
8pm–5am—

Scale runs 70% to 90%. Rows with fewer than 30 flights show a dash.

The early departures do better, though not dramatically: 85.4% on time for the 8am–11am window against 78.7% for 5pm–8pm. Worth taking if the schedule allows, not worth an extra connection. The 5pm–8pm window is the busiest, with 79 flights scheduled in it.

Across the year

Frontier on LAX to SJC through the year

Oct–Dec 202511 flights—
Jan–Mar 202634 flights85.3%
Apr–Jun 202651 flights79.2%
Jul–Sep 202642 flights80.0%

Scale runs 70% to 90%. Rows with fewer than 30 flights show a dash.

Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 80.5% on time across 138 flights.

Quarter by quarter Frontier on LAX to SJC held fairly steady: 85.3% in Jan–Mar 2026, 79.2% in Apr–Jun 2026 and 80.0% in Jul–Sep 2026. A spread of 6 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.

Arrival by arrival

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

The 26 late arrivals split 10 under half an hour, 10 between 30 and 60 minutes, and 6 an hour or more.

15+ min early31 flights23.3%
Within 15 min76 flights57.1%
15–29 min late10 flights7.5%
30–59 min late10 flights7.5%
1–2 hours late4 flights3.0%
2+ hours late2 flights1.5%

Scale runs 0% to 100%.

Share of 133 completed flights by arrival against schedule.

5 of 30 late departures made up the time and arrived on time, 17% of them. Only 1 left on time and still arrived late.

The worst days

Worst days for Frontier on LAX to SJC

The latest arrival of the period was on 8 March 2026, 2 hours 33 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The same cause led on five of the five worst days.

The latest arrivals of Frontier on LAX to SJC in the period
Date	Arrived late by	Largest filed cause
8 March 2026	2 hours 33 minutes	Late-arriving aircraft
21 December 2025	2 hours 17 minutes	Late-arriving aircraft
11 July 2026	1 hour 55 minutes	Late-arriving aircraft
3 May 2026	1 hour 34 minutes	Late-arriving aircraft
24 May 2026	1 hour 16 minutes	Late-arriving aircraft

Delay causes

Why Frontier runs late on this route

Late-arriving aircraft accounts for 88% of the 1,293 delay minutes carriers reported here, and the remaining four split what is left.

Late-arriving aircraft
88%
Carrier
8%
National Airspace System
4%

88% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 1,293 reported delay minutes here, that single category outweighs weather by 88 to one. The split is drawn from 1,293 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 85.4% on time here.

Cancellations run at 3.62%, against 1.89% nationally. That is about one flight in 30 cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.

Connections and stage length

What a delay here costs

Badly late arrivals are rare here: only 4.5% 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.

At 308 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 75.8% on time across 138 flights, 5 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 5 points of difference.

One caution: this is a thin sample. 138 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 SJC

Put together: the delay figures matter less here than the 3.62% cancellation rate. A late arrival costs you about 50 minutes; a cancelled flight costs you the day. Book the 8am–11am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 133 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