Carrier route record
UALAS→ORD
United Airlines · Las Vegas to Chicago
- Flights
- 2,330
- Period
- July 2025 to June 2026
- Share of route
- 44%
- Carriers
- 5
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with United Airlines.
United on LAS to ORD 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 a little over an hour on average. That is a workable record, not a spotless one. That rests on 2,330 flights. The strongest carrier on the route with a full sample, American Airlines, flew 1,848 at 76.2% on time.
The US average over the same twelve months is 77.6%, so there is little to separate United on LAS to ORD from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
79.3%
Arrivals under 15 minutes late, of 2,307 completed flights
Avg delay
71 min
Across delayed arrivals only, not all flights
Cancelled
0.43%
National rate is 1.81%
Whole route
76.5%
Every carrier on LAS to ORD, 5,297 flights
These figures cover 2,330 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 LAS to ORD
United flew 2,330 of the 5,297 flights on LAS to ORD, about 44% of it. Its 79.3% on time is 3 points better than the route as a whole, which runs 76.5%. Ranked by on-time rate it is number two of five carriers on the route, where the range runs from Spirit at 83.6% to Southwest at 66.6%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The choice of carrier is not cosmetic here. American Airlines arrives on time 76.2% of the time; Southwest Airlines manages 66.6%. Sample sizes sit next to every figure, because a two-point gap across 669 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Spirit Airlinesthin sample | 266 | 83.6% | 54 min | 1.50% | B |
| United Airlines (this page) | 2,330 | 79.3% | 71 min | 0.43% | B+ |
| American Airlines | 1,848 | 76.2% | 99 min | 2.27% | B |
| Frontier Airlinesthin sample | 184 | 68.6% | 88 min | 4.35% | C− |
| Southwest Airlines | 669 | 66.6% | 58 min | 0.30% | C+ |
American leads Southwest by 10 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Flight by flight
United flight numbers on LAS to ORD
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 25 points, against 10 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am353 flights89.4%
- 8am–11am363 flights86.0%
- 11am–2pm434 flights65.9%
- 2pm–5pm499 flights69.0%
- 5pm–8pm248 flights79.4%
- 8pm–5am433 flights90.7%
Scale runs 55% to 95%. Rows with fewer than 30 flights show a dash.
The weak window here is the middle of the day, not the evening: 11am–2pm runs 65.9% on time against 90.7% for 8pm–5am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 2pm–5pm window is the busiest, with 499 flights scheduled in it.
Across the year
United on LAS to ORD through the year
July is the worst month at 70.0% on time, 18 points below February, the best at 88.0%. 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. May was the busiest month here, with 221 flights.
Across the week, Tuesday is the strongest day at 87.5% on time and Friday the weakest at 75.0%. 13 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 49% of the 34,000 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.
- 49%National Airspace System
- 29%Late-arriving aircraft
- 21%Carrier
- 1%Extreme weather
49% 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 17,000 minutes out of 34,000, against a national NAS share of 21%. The split is drawn from 33,892 reported delay minutes.
Cancellations are rare at 0.43%, 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
7.0% 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 a little over an hour, which a normal layover absorbs.
At 1,514 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The return leg runs 79.6% on time across 2,328 flights, within half a point 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 2,330 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 LAS to ORD
Put together: the calendar is the biggest lever here, not the carrier or the hour. February runs 88.0% on time and July 70.0%, a swing of 18 points. If the dates move at all, move them out of July before you think about anything else. 2,307 completed flights over 12 months sit behind that.
Related
Where to go next
- LAS to ORD, every carrier
- United on ORD to LAS, the return leg
- Spirit Airlines on LAS to ORD83.6%
- American Airlines on LAS to ORD76.2%
- Frontier Airlines on LAS to ORD68.6%
- Southwest Airlines on LAS to ORD66.6%
- United Airlines network-wide record
- Harry Reid International (LAS) delay statistics
- Chicago O'Hare International (ORD) delay statistics
- The best time of day to fly, according to 7.04 million flight records
- Worst months to fly in the US, ranked by the data
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.