Carrier route record
UALAX→SFO
United Airlines · Los Angeles to San Francisco
- Flights
- 3,257
- Period
- July 2025 to June 2026
- Share of route
- 30%
- Carriers
- 7
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with United Airlines.
United on LAX to SFO draws a C+. About one flight in three arrives at least 15 minutes late, and the typical late arrival is about an hour behind schedule. Build slack into anything you connect to. That rests on 3,257 flights. The strongest carrier on the route with a full sample, SkyWest Airlines, flew 2,593 at 72.0% on time.
SkyWest Airlines is the most reliable of the five carriers covered here at 72.0% on time across 2,593 flights.
Key figures
On time
66.3%
Arrivals under 15 minutes late, of 3,249 completed flights
Avg delay
57 min
Across delayed arrivals only, not all flights
Cancelled
0.25%
National rate is 1.81%
Whole route
64.8%
Every carrier on LAX to SFO, 11,013 flights
These figures cover 3,257 flights between July 2025 and June 2026. Beyond the headline rate, 9.9% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Carrier by carrier
United against every carrier on LAX to SFO
United flew 3,257 of the 11,013 flights on LAX to SFO, about 30% of it. Its 66.3% on time is 2 points better than the route as a whole, which runs 64.8%. Ranked by on-time rate it is number two of seven carriers on the route, where the range runs from SkyWest at 72.0% to Alaska at 52.3%. One 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 72.0% of the time; Alaska Airlines manages 52.3%. Sample sizes sit next to every figure, because a two-point gap across 686 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlines | 2,593 | 72.0% | 59 min | 1.16% | C |
| United Airlines (this page) | 3,257 | 66.3% | 57 min | 0.25% | C+ |
| Delta Air Lines | 2,373 | 65.2% | 55 min | 1.52% | C |
| American Airlinesthin sample | 343 | 61.3% | 74 min | 0.29% | D+ |
| Southwest Airlines | 1,370 | 57.1% | 61 min | 0.36% | D+ |
| Frontier Airlines | 391 | 53.3% | 72 min | 2.05% | F |
| Alaska Airlines | 686 | 52.3% | 55 min | 0.44% | F+ |
The spread between SkyWest and Alaska is 20 points, wide enough that it should decide the booking. On a hundred trips that is 20 more arrivals inside the on-time window.
Flight by flight
United flight numbers on LAX to SFO
Departure window
When United runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 29 points, against 20 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am402 flights81.7%
- 8am–11am549 flights53.3%
- 11am–2pm611 flights74.3%
- 2pm–5pm418 flights73.1%
- 5pm–8pm711 flights67.2%
- 8pm–5am566 flights53.2%
Scale runs 45% to 85%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 53.2% on time, against 81.7% for the 5am–8am 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 5pm–8pm window is the busiest, with 711 flights scheduled in it.
Across the year
United on LAX to SFO through the year
Delays peak in May, when the on-time rate falls to 48.0%. March is the strongest month at 87.8%. Moving a flexible trip across that boundary buys 40 points. May was the busiest month here, with 302 flights.
Across the week, Tuesday is the strongest day at 74.2% on time and Sunday the weakest at 59.7%. 15 points is a smaller lever than departure hour, but it is free.
Delay causes
Why United runs late on this route
One category carries most of the weight here. National Airspace System accounts for 64% of the 63,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 64%National Airspace System
- 23%Late-arriving aircraft
- 12%Carrier
- 1%Extreme weather
64% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 40,000 minutes out of 63,000, against a national NAS share of 21%. The split is drawn from 62,628 reported delay minutes.
Cancellations are rare at 0.25%, below the national 1.81% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 9.9% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum 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 5am–8am window matters as much as it does.
The return leg is a different operation and performs like one: it runs 78.4% on time across 3,263 flights, 12 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 12 points of difference.
The sample behind these figures is 3,257 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
What to do with this
Booking United on LAX to SFO
Put together: the calendar is the biggest lever here, not the carrier or the hour. March runs 87.8% on time and May 48.0%, a swing of 40 points. If the dates move at all, move them out of May before you think about anything else. 3,249 completed flights over 12 months sit behind that.
Related
Where to go next
- LAX to SFO, every carrier
- United on SFO to LAX, the return leg
- SkyWest Airlines on LAX to SFO72.0%
- Delta Air Lines on LAX to SFO65.2%
- American Airlines on LAX to SFO61.3%
- Southwest Airlines on LAX to SFO57.1%
- Frontier Airlines on LAX to SFO53.3%
- Alaska Airlines on LAX to SFO52.3%
- United Airlines network-wide record
- Los Angeles International (LAX) delay statistics
- San Francisco International (SFO) delay statistics
- Same route, different airline: where the carrier you pick matters most
- The best time of day to fly, according to 7.04 million flight records
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.