Flight number record
UA 1181
United Airlines · Las Vegas to Houston
- Route
- LAS → IAH
- Departs
- 08:00
- Flights
- 270
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 2026, not live status. For today’s UA 1181, check with United Airlines.
UA 1181 earns an A. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 14 points better than the national rate of 77.6%. When something does go wrong the average delay runs close to two hours. That rests on 270 flights, with a median arrival 11 minutes early.
Set against the rest of the country, UA 1181's record is 14 points better than the US average of 77.6%. That gap is worth roughly 140 fewer late arrivals for every thousand flights.
Key figures
On time
91.6%
Arrivals under 15 minutes late, of 263 completed flights
Avg delay
107 min
Across delayed arrivals only, not all flights
Cancelled
1.11%
National rate is 1.81%
1 hour+ late
3.0%
National rate is 8.1%
These figures cover 270 flights between July 2025 and June 2026. The median arrival is 11 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.
Schedule
When UA 1181 flies
UA 1181 flies LAS to IAH without a single fixed slot. Its most common scheduled departure was 08:00, used on 166 of 270 flights, with 08:15 (49 flights) and 08:05 (31 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 08:00166 flights61.5%
- Departs 08:1549 flights18.1%
- Departs 08:0531 flights11.5%
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 08:00 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 84.1%, and UA 1181 runs 8 points better at 91.6%. 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 1181 next to LAS to IAH
Every carrier on LAS to IAH combined arrived on time 83.9% of the time across 3,455 flights, so UA 1181 is 8 points ahead of it. United flew 2,601 flights on the same city pair under all its flight numbers, including this one, and those ran 85.6% on time. Across its whole network United Airlines managed 79.0%, which this flight beats by 13 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 1181thin sample | 270 | 91.6% | 107 min | 1.11% | A |
| All United Airlines on LAS–IAH | 2,601 | 85.6% | 73 min | 0.58% | A+ |
| All carriers on LAS–IAH | 3,455 | 83.9% | 75 min | 0.93% | B+ |
| United Airlines, whole network | 821,041 | 79.0% | 72 min | 1.01% | B |
Across the year
UA 1181 quarter by quarter
UA 1181 did not run the same all year. Its best quarter was Jan–Mar 2026 at 98.1% on time and its weakest Apr–Jun 2026 at 83.8%, a swing of 14 points on roughly 68 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 202555 flights92.2%
- Oct–Dec 202592 flights93.4%
- Jan–Mar 202653 flights98.1%
- Apr–Jun 202670 flights83.8%
Scale runs 75% to 100%. Rows with fewer than 30 flights show a dash.
By weekday, UA 1181 ranged from 86.1% on Wednesday to 97.3% on Saturday. With about 39 flights behind each day, a spread of 11 points is inside normal variation, so the day you fly is not worth changing for this flight.
Delay causes
Why UA 1181 runs late
One category carries most of the weight here. Carrier accounts for 42% of the 2,342 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.
- 42%Carrier
- 33%Late-arriving aircraft
- 23%National Airspace System
- 2%Extreme weather
The largest share of delay minutes, 42%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 993 of the 2,342 delay minutes reported here. The split is drawn from 2,342 delay minutes reported on UA 1181.
Cancellations sit at 1.11% against a national 1.81%, which is ordinary. Diversions add another 1.48%.
Connections and routes
What a delay on this flight costs
Badly late arrivals are rare here: only 3.0% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
The 1,222 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The same number turns up on eight other city pairs in the data, including IAH to DCA (55), DEN to ORD (37) and IAH to SFO (37), but none flew often enough under UA 1181 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to LAS to IAH only.
One caution: this is a thin sample. 270 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 1181
For a booking, UA 1181 has one of the better records a US domestic flight can show: 91.6% on time and 1.11% cancelled. That is a base rate, not a promise about any single day.
Related
Where to go next
- LAS to IAH, every carrier and departure
- IAH to LAS, the return direction
- United Airlines 1711 on the same route88.1%
- United Airlines 2608 on the same route95.3%
- United Airlines 2492 on the same route81.1%
- Harry Reid International (LAS) delay statistics
- George Bush Intercontinental (IAH) 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
- Why the first flight of the morning is statistically safest
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.