Carrier route record
UASFO→LAS
United Airlines · San Francisco to Las Vegas
- Flights
- 2,757
- Period
- July 2025 to June 2026
- Share of route
- 45%
- Carriers
- 5
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with United Airlines.
United on SFO to LAS lands a B+, 2 points better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about 55 minutes on average. That is a workable record, not a spotless one. That rests on 2,757 flights. The strongest carrier on the route with a full sample, Alaska Airlines, flew 1,116 at 76.5% on time.
The US average over the same twelve months is 77.6%, so there is little to separate United on SFO to LAS from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
79.6%
Arrivals under 15 minutes late, of 2,742 completed flights
Avg delay
55 min
Across delayed arrivals only, not all flights
Cancelled
0.36%
National rate is 1.81%
Whole route
74.1%
Every carrier on SFO to LAS, 6,066 flights
These figures cover 2,757 flights between July 2025 and June 2026. The median arrival is 5 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.
Carrier by carrier
United against every carrier on SFO to LAS
United flew 2,757 of the 6,066 flights on SFO to LAS, about 45% of it. Its 79.6% on time is 6 points better than the route as a whole, which runs 74.1%. Ranked by on-time rate it is first of five carriers on the route, where the range runs from United at 79.6% to SkyWest at 50.0%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The choice of carrier is not cosmetic here. Alaska Airlines arrives on time 76.5% of the time; Frontier Airlines manages 65.6%. Sample sizes sit next to every figure, because a two-point gap across 879 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines (this page) | 2,757 | 79.6% | 55 min | 0.36% | B+ |
| Alaska Airlines | 1,116 | 76.5% | 66 min | 0.81% | B+ |
| Southwest Airlines | 1,312 | 66.3% | 64 min | 0.53% | C+ |
| Frontier Airlines | 879 | 65.6% | 96 min | 1.25% | C |
| SkyWest Airlinesthin sample | 2 | 50.0% | 81 min | 0.00% | F+ |
Alaska leads Frontier by 11 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Flight by flight
United flight numbers on SFO to LAS
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 35 points, against 11 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am176 flights98.3%
- 8am–11am549 flights87.4%
- 11am–2pm548 flights76.9%
- 2pm–5pm267 flights63.3%
- 5pm–8pm520 flights78.8%
- 8pm–5am697 flights77.7%
Scale runs 55% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 98.3% of the time, against 63.3% for the afternoon window. That is 35 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8pm–5am window is the busiest, with 697 flights scheduled in it.
Across the year
United on SFO to LAS through the year
Delays peak in May, when the on-time rate falls to 65.5%. August is the strongest month at 86.8%. Moving a flexible trip across that boundary buys 21 points. June was the busiest month here, with 256 flights.
Across the week, Saturday is the strongest day at 88.7% on time and Thursday the weakest at 74.5%. 14 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. Late-arriving aircraft accounts for 47% of the 31,000 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.
- 47%Late-arriving aircraft
- 28%National Airspace System
- 25%Carrier
- 0%Extreme weather
47% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 31,000 reported delay minutes here, that single category outweighs weather by 47 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 30,652 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 98.3% on time here.
Cancellations are rare at 0.36%, 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
6.5% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about 55 minutes, which a normal layover absorbs.
At 414 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 67.5% on time across 2,756 flights, 12 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 12 points of difference.
The sample behind these figures is 2,757 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 SFO to LAS
Put together: the calendar is the biggest lever here, not the carrier or the hour. August runs 86.8% on time and May 65.5%, a swing of 21 points. If the dates move at all, move them out of May before you think about anything else. 2,742 completed flights over 12 months sit behind that.
Related
Where to go next
- SFO to LAS, every carrier
- United on LAS to SFO, the return leg
- Alaska Airlines on SFO to LAS76.5%
- Southwest Airlines on SFO to LAS66.3%
- Frontier Airlines on SFO to LAS65.6%
- United Airlines network-wide record
- San Francisco International (SFO) delay statistics
- Harry Reid International (LAS) delay statistics
- Same route, different airline: where the carrier you pick matters most
- Why the first flight of the morning is statistically safest
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.