Flight number record
UA 1791
United Airlines · Los Angeles to San Francisco
- Route
- LAX → SFO
- Departs
- 10:26
- Flights
- 336
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 2026, not live status. For today’s UA 1791, check with United Airlines.
UA 1791 earns a D+, which is as low as this site's scale goes for a reason. Only 57.4% of flights arrive inside the 15-minute window, 20 points worse than the national rate of 77.6%. Late arrivals average roughly 45 minutes. Treat any tight connection here as a coin flip. That rests on 336 flights, with a median arrival 8 minutes late.
The national on-time rate over the same period is 77.6%, so UA 1791 runs 20 points behind the country as a whole. Across a thousand flights that is about 202 extra late arrivals.
Key figures
On time
57.4%
Arrivals under 15 minutes late, of 336 completed flights
Avg delay
47 min
Across delayed arrivals only, not all flights
Cancelled
0.00%
National rate is 1.81%
1 hour+ late
10.1%
National rate is 8.1%
These figures cover 336 flights between July 2025 and June 2026. Beyond the headline rate, 10.1% 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.
Schedule
When UA 1791 flies
UA 1791 flies LAX to SFO without a single fixed slot. Its most common scheduled departure was 10:26, used on 174 of 336 flights, with 10:15 (46 flights) and 10:27 (35 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 10:26174 flights51.8%
- Departs 10:1546 flights13.7%
- Departs 10:2735 flights10.4%
Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 10:26 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 84.1%, and UA 1791 runs 27 points worse at 57.4%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
Against the route
UA 1791 next to LAX to SFO
Every carrier on LAX to SFO combined arrived on time 64.8% of the time across 11,013 flights, so UA 1791 is 7 points behind it. United flew 3,257 flights on the same city pair under all its flight numbers, including this one, and those ran 66.3% on time. Across its whole network United Airlines managed 79.0%, which this flight trails by 22 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 1791thin sample | 336 | 57.4% | 47 min | 0.00% | D+ |
| All United Airlines on LAX–SFO | 3,257 | 66.3% | 57 min | 0.25% | C+ |
| All carriers on LAX–SFO | 11,013 | 64.8% | 59 min | 0.83% | D+ |
| United Airlines, whole network | 821,041 | 79.0% | 72 min | 1.01% | B |
Across the year
UA 1791 quarter by quarter
UA 1791 did not run the same all year. Its best quarter was Jan–Mar 2026 at 71.6% on time and its weakest Apr–Jun 2026 at 36.5%, a swing of 35 points on roughly 84 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.
- Jul–Sep 202580 flights68.8%
- Oct–Dec 202583 flights53.0%
- Jan–Mar 202688 flights71.6%
- Apr–Jun 202685 flights36.5%
Scale runs 30% to 75%. Rows with fewer than 30 flights show a dash.
By weekday, UA 1791 ranged from 51.5% on Saturday to 61.7% on Wednesday. With about 48 flights behind each day, a spread of 10 points is inside normal variation, so the day you fly is not worth changing for this flight.
Delay causes
Why UA 1791 runs late
One category carries most of the weight here. National Airspace System accounts for 79% of the 6,723 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.
- 79%National Airspace System
- 15%Late-arriving aircraft
- 6%Carrier
79% 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 5,325 minutes out of 6,723, against a national NAS share of 21%. The split is drawn from 6,723 delay minutes reported on UA 1791.
Cancellations are rare at 0.00%, below the national 1.81% and low enough to earn the plus on the grade. Almost no flights are called off; the risk here is arriving late, not not arriving.
Connections and routes
What a delay on this flight costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 10.1% 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.
The same number turns up on seven other city pairs in the data, including SFO to IAD (62), SFO to ORD (49) and SFO to DTW (27), but none flew often enough under UA 1791 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to LAX to SFO only.
One caution: this is a thin sample. 336 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 UA 1791
For a booking, UA 1791 is one of the weaker ways to fly LAX to SFO: 7 points below the route as a whole. If the schedule allows, compare it with the other departures listed on the route page before settling on this one.
Related
Where to go next
- LAX to SFO, every carrier and departure
- SFO to LAX, the return direction
- Delta Air Lines 2267 on the same route53.2%
- United Airlines 2019 on the same route70.3%
- Delta Air Lines 1421 on the same route94.7%
- Delta Air Lines 1559 on the same route70.7%
- Delta Air Lines 2272 on the same route62.9%
- Delta Air Lines 1715 on the same route51.7%
- Los Angeles International (LAX) delay statistics
- San Francisco International (SFO) delay statistics
- United Airlines on-time record
- Every United Airlines flight number with a record
- The most and least reliable flight numbers in the US
- How often a connection fails at the major US hubs
A flight number here means United Airlines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.
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.