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DelayAtlas

Carrier route record

UALAXLAS

United Airlines · Los Angeles to Las Vegas

Flights
1,572
Period
July 2025 to June 2026
Share of route
19%
Carriers
8
B+GRADE

Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with United Airlines.

United on LAX to LAS lands a B+, 6 points better than the national rate of 77.6%. About one flight in six arrives 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 1,572 flights. The strongest carrier on the route with a full sample, Spirit Airlines, flew 640 at 84.9% on time.

Spirit Airlines is the most reliable of the five carriers covered here at 84.9% on time across 640 flights.

Key figures

On time

83.6%

Arrivals under 15 minutes late, of 1,564 completed flights

Avg delay

58 min

Across delayed arrivals only, not all flights

Cancelled

0.51%

National rate is 1.81%

Whole route

76.5%

Every carrier on LAX to LAS, 8,319 flights

These figures cover 1,572 flights between July 2025 and June 2026. The median arrival is 8 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 LAX to LAS

United flew 1,572 of the 8,319 flights on LAX to LAS, about 19% of it. Its 83.6% on time is 7 points better than the route as a whole, which runs 76.5%. Ranked by on-time rate it is number three of eight carriers on the route, where the range runs from SkyWest at 87.3% to Alaska at 64.7%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The choice of carrier is not cosmetic here. Spirit Airlines arrives on time 84.9% of the time; American Airlines manages 68.5%. Sample sizes sit next to every figure, because a two-point gap across 1,064 flights means less than a ten-point one.

On-time performance by carrier on LAX to LAS
AirlineFlightsOn timeAvg delayCancelledGrade
SkyWest Airlinesthin sample31187.3%49 min1.61%A
Spirit Airlines64084.9%76 min0.94%B+
United Airlines (this page)1,57283.6%58 min0.51%B+
Delta Air Lines1,73578.5%59 min0.81%B+
Southwest Airlines2,38672.2%53 min0.59%C+
Frontier Airlines59470.0%79 min1.35%C
American Airlines1,06468.5%87 min0.85%C+
Alaska Airlinesthin sample1764.7%28 min0.00%D+

The spread between Spirit and American is 16 points, wide enough that it should decide the booking. On a hundred trips that is 16 more arrivals inside the on-time window.

Flight by flight

United flight numbers on LAX 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 13 points, against 16 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

  • 5am–8am3 flights
  • 8am–11am356 flights91.8%
  • 11am–2pm231 flights80.3%
  • 2pm–5pm310 flights78.8%
  • 5pm–8pm313 flights81.8%
  • 8pm–5am359 flights83.0%

Scale runs 70% to 95%. Rows with fewer than 30 flights show a dash.

Book the morning departure. Flights leaving between 8am–11am arrive on time 91.8% of the time, against 78.8% for the afternoon window. That is 13 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 359 flights scheduled in it.

Across the year

United on LAX to LAS through the year

On-time rate by calendar month81J85F86M87A82M78J82J81A82S89O86N82D
Darker means more delays. Figures are on-time percentages.October best, June worst

June is the worst month at 77.9% on time, 11 points below October, the best at 89.3%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. December was the busiest month here, with 148 flights.

Across the week, Wednesday is the strongest day at 92.3% on time and Friday the weakest at 77.4%. 15 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week81.4Mon87.7Tue92.3Wed77.9Thu77.4Fri86.3Sat83.9Sun
Monday: 81.4 percent on time. Tuesday: 87.7 percent on time. Wednesday: 92.3 percent on time. Thursday: 77.9 percent on time. Friday: 77.4 percent on time. Saturday: 86.3 percent on time. Sunday: 83.9 percent on time

Delay causes

Why United runs late on this route

Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 15,000 reported delay minutes.

  • Late-arriving aircraft
    38%
  • National Airspace System
    38%
  • Carrier
    22%
  • Extreme weather
    3%

38% 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 15,000 reported delay minutes here, that single category outweighs weather by 15 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 14,915 reported delay minutes.

38% 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 5,644 minutes out of 15,000, against a national NAS share of 21%.

Cancellations are rare at 0.51%, 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

5.6% 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 an hour, which a normal layover absorbs.

At 236 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 8am–11am window matters as much as it does.

The return leg runs 86.2% on time across 1,574 flights, within 3 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

The sample behind these figures is 1,572 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 LAS

Put together: take the 8am–11am departure, avoid June if the dates are flexible, and if two carriers are within a few dollars of each other, Spirit is the one with the record behind it. None of that guarantees an on-time arrival; it moves the odds by 16 points, which is the most any booking decision can do. 1,564 completed flights over 12 months sit behind that.

Related

Where to go next

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.