Carrier route record

F9SJC→LAX

Frontier Airlines · San Jose to Los Angeles

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 SJC to LAX sits in the middle of the pack with a B−. Close to three flights in four arrive on time by the DOT's definition, 2 points worse than the national rate of 77.3%. The late ones land roughly 45 minutes behind schedule. That rests on 138 flights. The strongest carrier on the route with a full sample, SkyWest Airlines, flew 1,809 at 91.7% on time.

SkyWest Airlines is the most reliable of the three carriers covered here at 91.7% on time across 1,809 flights.

On time

75.8%

Arrivals under 15 minutes late, of 132 completed flights

Avg delay

43 min

Across delayed arrivals only, not all flights

Cancelled

4.35%

National rate is 1.89%

Whole route

85.0%

Every carrier on SJC to LAX, 4,470 flights

These figures cover 138 flights between September 2025 and August 2026. The median arrival is 4 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 SJC to LAX

Frontier flew 138 of the 4,470 flights on SJC to LAX, about 3% of it. Its 75.8% on time is 9 points worse than the route as a whole, which runs 85.0%. 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 91.7% of the time; Southwest Airlines manages 76.8%. Sample sizes sit next to every figure, because a two-point gap across 1,867 flights means less than a ten-point one.

On-time performance by carrier on SJC to LAX
Airline	Flights	On time	Avg delay	Cancelled	Grade
United Airlinesthin sample	1	100.0%	—	0.00%	A+
SkyWest Airlines	1,809	91.7%	76 min	0.44%	A+
Delta Air Lines	649	91.6%	57 min	2.31%	A
Southwest Airlines	1,867	76.8%	47 min	0.64%	B+
Frontier Airlines (this page)thin sample	138	75.8%	43 min	4.35%	B−
American Airlinesthin sample	6	66.7%	29 min	0.00%	C+

The spread between SkyWest and Southwest is 15 points, wide enough that it should decide the booking. On a hundred trips that is 15 more arrivals inside the on-time window.

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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 13 points, against 15 points between the best and worst carrier.

5am–8am—
8am–11am7 flights—
11am–2pm26 flights—
2pm–5pm5 flights—
5pm–8pm37 flights77.1%
8pm–5am63 flights64.4%

Scale runs 55% to 85%. Rows with fewer than 30 flights show a dash.

The 8pm–5am window is where this operation falls apart: 64.4% on time, against 77.1% for the 5pm–8pm slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 8pm–5am window is the busiest, with 63 flights scheduled in it.

Across the year

Frontier on SJC to LAX through the year

Oct–Dec 202511 flights—
Jan–Mar 202634 flights81.8%
Apr–Jun 202651 flights83.7%
Jul–Sep 202642 flights60.0%

Scale runs 50% 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 75.8% on time across 138 flights.

Frontier on SJC to LAX did not run the same all year. Its best quarter was Apr–Jun 2026 at 83.7% on time and its weakest Jul–Sep 2026 at 60.0%, a swing of 24 points on roughly 46 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.

Arrival by arrival

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

Most of the lateness is short. 16 of the 32 late arrivals were under half an hour behind, and 6 reached an hour or more.

15+ min early32 flights24.2%
Within 15 min68 flights51.5%
15–29 min late16 flights12.1%
30–59 min late10 flights7.6%
1–2 hours late4 flights3.0%
2+ hours late2 flights1.5%

Scale runs 0% to 100%.

Share of 132 completed flights by arrival against schedule.

3 of 23 late departures made up the time and arrived on time, 13% of them. In the other direction, 12 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at LAX.

The worst days

Worst days for Frontier on SJC to LAX

The latest arrival of the period was on 1 January 2026, 3 hours 2 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 SJC to LAX in the period
Date	Arrived late by	Largest filed cause
1 January 2026	3 hours 2 minutes	Late-arriving aircraft
17 April 2026	2 hours 31 minutes	Late-arriving aircraft
24 May 2026	1 hour 29 minutes	Late-arriving aircraft
11 July 2026	1 hour 29 minutes	Late-arriving aircraft
4 January 2026	1 hour 24 minutes	Late-arriving aircraft

Delay causes

Why Frontier runs late on this route

Late-arriving aircraft accounts for 70% of the 1,381 delay minutes carriers reported here, and the remaining four split what is left.

Late-arriving aircraft
70%
National Airspace System
25%
Carrier
5%

70% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 1,381 reported delay minutes here, that single category outweighs weather by 70 to one. The split is drawn from 1,381 reported delay minutes.

Cancellations run at 4.35%, against 1.89% nationally. That is roughly one flight in 25 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 5pm–8pm window matters as much as it does.

The return leg is a different operation and performs like one: it runs 80.5% on time across 138 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. 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 SJC to LAX

Put together: the delay figures matter less here than the 4.35% cancellation rate. A late arrival costs you roughly 45 minutes; a cancelled flight costs you the day. Book the 5pm–8pm departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 132 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