Flight number record
UA 1181
United Airlines · Las Vegas to Houston
- Route
- LAS → IAH
- Departs
- 08:00
- Flights
- 262
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 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 12 points better than the national rate of 77.3%. When something does go wrong the average delay runs an hour and a half. That rests on 262 flights, with a median arrival 11 minutes early.
Set against the rest of the country, UA 1181's record is 12 points better than the US average of 77.3%. That gap is worth roughly 123 fewer late arrivals for every thousand flights.
Key figures
On time
89.6%
Arrivals under 15 minutes late, of 259 completed flights
Avg delay
99 min
Across delayed arrivals only, not all flights
Cancelled
0.38%
National rate is 1.89%
1 hour+ late
3.5%
National rate is 8.3%
These figures cover 262 flights between September 2025 and August 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.
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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 207 of 262 flights, with 08:05 (31 flights) next.
- Departs 08:00207 flights79.0%
- Departs 08:0531 flights11.8%
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 08:00 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 83.9%, and UA 1181 runs 6 points better at 89.6%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
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Against the route
UA 1181 next to LAS to IAH
Every carrier on LAS to IAH combined arrived on time 84.2% of the time across 3,411 flights, so UA 1181 is 5 points ahead of it. United flew 2,596 flights on the same city pair under all its flight numbers, including this one, and those ran 85.8% on time. Across its whole network United Airlines managed 78.8%, which this flight beats by 11 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 1181thin sample | 262 | 89.6% | 99 min | 0.38% | A+ |
| All United Airlines on LAS–IAH | 2,596 | 85.8% | 74 min | 0.35% | A+ |
| All carriers on LAS–IAH | 3,411 | 84.2% | 78 min | 0.85% | B+ |
| United Airlines, whole network | 830,825 | 78.8% | 73 min | 1.02% | 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 Jul–Sep 2026 at 78.0%, a swing of 20 points on roughly 66 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 20256 flights—
- Oct–Dec 202592 flights93.4%
- Jan–Mar 202653 flights98.1%
- Apr–Jun 202670 flights83.8%
- Jul–Sep 202641 flights78.0%
Scale runs 70% to 100%. Rows with fewer than 30 flights show a dash.
By weekday, UA 1181 did best on Sunday at 94.7% on time and worst on Monday at 81.1%. Each day rests on about 37 flights, so a gap of 14 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late UA 1181 runs when it is late
UA 1181 often beats the schedule: 92 of 259 completed flights, 36%, arrived 15 minutes or more early. The 27 late arrivals split 13 under half an hour, 5 between 30 and 60 minutes, and 9 an hour or more.
- 15+ min early92 flights35.5%
- Within 15 min140 flights54.1%
- 15–29 min late13 flights5.0%
- 30–59 min late5 flights1.9%
- 1–2 hours late4 flights1.5%
- 2+ hours late5 flights1.9%
Scale runs 0% to 100%.
Share of 259 completed flights by arrival against schedule.
Only 18 of 259 completed flights left 15 minutes late or more, too few to say how often the time is made up.
The worst days
Worst days for UA 1181
The latest arrival of the period was on 27 October 2025, 11 hours 40 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. On four of the five worst days the largest share was filed as carrier-caused (crew, maintenance, fuelling, baggage).
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 27 October 2025 | 11 hours 40 minutes | Late-arriving aircraft |
| 3 June 2026 | 7 hours 17 minutes | Carrier |
| 14 July 2026 | 4 hours 51 minutes | Carrier |
| 9 June 2026 | 4 hours 2 minutes | Carrier |
| 8 July 2026 | 2 hours | Carrier |
Delay causes
Why UA 1181 runs late
Carrier accounts for 53% of the 2,685 delay minutes carriers reported here, and the remaining four split what is left.
- 53%Carrier
- 31%Late-arriving aircraft
- 15%National Airspace System
- 2%Extreme weather
The largest share of delay minutes, 53%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 1,411 of the 2,685 delay minutes reported here. The split is drawn from 2,685 delay minutes reported on UA 1181.
Cancellations are rare at 0.38%, below the national 1.89% 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 routes
What a delay on this flight costs
Badly late arrivals are rare here: only 3.5% land an hour or more behind schedule, against 8.3% 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.
The same number turns up on nine other city pairs in the data, including IAH to DCA (55), IAH to SFO (37) and IAH to FLL (31), 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. 262 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: 89.6% on time and 0.38% 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 route90.2%
- United Airlines 2608 on the same route95.0%
- 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
- Worst months to fly in the US, ranked by the data
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.