Flight number record
UA 1791
United Airlines · Los Angeles to San Francisco
- Route
- LAX → SFO
- Departs
- 10:26
- Flights
- 316
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 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 55.4% of flights arrive inside the 15-minute window, 22 points worse than the national rate of 77.3%. Late arrivals average roughly 45 minutes. Treat any tight connection here as a coin flip. That rests on 316 flights, with a median arrival 11 minutes late.
The national on-time rate over the same period is 77.3%, so UA 1791 runs 22 points behind the country as a whole. Across a thousand flights that is about 219 extra late arrivals.
Key figures
On time
55.4%
Arrivals under 15 minutes late, of 316 completed flights
Avg delay
46 min
Across delayed arrivals only, not all flights
Cancelled
0.00%
National rate is 1.89%
1 hour+ late
11.1%
National rate is 8.3%
These figures cover 316 flights between September 2025 and August 2026. Beyond the headline rate, 11.1% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
Fare search by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
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 163 of 316 flights, with 10:55 (68 flights) and 10:27 (35 flights) next.
- Departs 10:26163 flights51.6%
- Departs 10:5568 flights21.5%
- Departs 10:2735 flights11.1%
Scale runs 0% to 100%.
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 83.9%, and UA 1791 runs 29 points worse at 55.4%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
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.
Against the route
UA 1791 next to LAX to SFO
Every carrier on LAX to SFO combined arrived on time 60.1% of the time across 11,437 flights, so UA 1791 is 5 points behind it. United flew 3,330 flights on the same city pair under all its flight numbers, including this one, and those ran 62.9% on time. Across its whole network United Airlines managed 78.8%, which this flight trails by 23 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 1791thin sample | 316 | 55.4% | 46 min | 0.00% | D+ |
| All United Airlines on LAX–SFO | 3,330 | 62.9% | 56 min | 0.12% | D+ |
| All carriers on LAX–SFO | 11,437 | 60.1% | 57 min | 0.80% | D+ |
| United Airlines, whole network | 830,825 | 78.8% | 73 min | 1.02% | 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 79 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 202527 flights—
- Oct–Dec 202583 flights53.0%
- Jan–Mar 202688 flights71.6%
- Apr–Jun 202685 flights36.5%
- Jul–Sep 202633 flights60.6%
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 59.6% on Sunday. With about 45 flights behind each day, a spread of 8 points is inside normal variation, so the day you fly is not worth changing for this flight.
Arrival by arrival
How late UA 1791 runs when it is late
The 141 late arrivals split 51 under half an hour, 55 between 30 and 60 minutes, and 35 an hour or more.
- 15+ min early48 flights15.2%
- Within 15 min127 flights40.2%
- 15–29 min late51 flights16.1%
- 30–59 min late55 flights17.4%
- 1–2 hours late29 flights9.2%
- 2+ hours late6 flights1.9%
Scale runs 0% to 100%.
Share of 316 completed flights by arrival against schedule.
15 of 84 late departures made up the time and arrived on time, 18% of them. In the other direction, 72 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 SFO.
The worst days
Worst days for UA 1791
The latest arrival of the period was on 28 May 2026, 4 hours 3 minutes behind schedule; most of its delay minutes were filed as national airspace system delay. The same cause led on four of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 28 May 2026 | 4 hours 3 minutes | National Airspace System |
| 20 April 2026 | 3 hours 8 minutes | National Airspace System |
| 23 February 2026 | 2 hours 52 minutes | Late-arriving aircraft |
| 3 January 2026 | 2 hours 23 minutes | National Airspace System |
| 24 June 2026 | 2 hours 11 minutes | National Airspace System |
Delay causes
Why UA 1791 runs late
National Airspace System accounts for 85% of the 6,539 delay minutes carriers reported here, and the remaining four split what is left.
- 85%National Airspace System
- 9%Late-arriving aircraft
- 6%Carrier
85% 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 5,540 minutes out of 6,539, against a national NAS share of 21%. The split is drawn from 6,539 delay minutes reported on UA 1791.
Cancellations are rare at 0.00%, below the national 1.89% 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
11.1% 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.
The same number turns up on seven other city pairs in the data, including SFO to IAD (121), SFO to DTW (27) and SAN to SFO (21), 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. 316 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, read UA 1791 as 55.4% on time with 0.00% cancelled over 316 flights. Those are rates from the past twelve months, not a forecast for any particular day.
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 route44.3%
- United Airlines 2019 on the same route65.1%
- Delta Air Lines 1421 on the same route94.1%
- Delta Air Lines 1559 on the same route65.7%
- Delta Air Lines 1715 on the same route48.3%
- Delta Air Lines 2986 on the same route57.1%
- 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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.