Carrier route record
UAIAH→LAX
United Airlines · Houston to Los Angeles
- Flights
- 3,421
- Period
- September 2025 to August 2026
- Share of route
- 66%
- Carriers
- 6
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with United Airlines.
United on IAH to LAX earns an A+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 8 points better than the national rate of 77.3%. When something does go wrong the average delay runs about an hour. That rests on 3,421 flights. The strongest carrier on the route with a full sample, Delta Air Lines, flew 648 at 87.7% on time.
Set against the rest of the country, United's IAH to LAX record is 8 points better than the US average of 77.3%. That gap is worth roughly 84 fewer late arrivals for every thousand flights.
Key figures
On time
85.7%
Arrivals under 15 minutes late, of 3,411 completed flights
Avg delay
57 min
Across delayed arrivals only, not all flights
Cancelled
0.20%
National rate is 1.89%
Whole route
84.1%
Every carrier on IAH to LAX, 5,147 flights
These figures cover 3,421 flights between September 2025 and August 2026. The median arrival is 9 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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Carrier by carrier
United against every carrier on IAH to LAX
United flew 3,421 of the 5,147 flights on IAH to LAX, most of the route. Its 85.7% on time is 2 points better than the route as a whole, which runs 84.1%. Ranked by on-time rate it is number three of six carriers on the route, where the range runs from American at 100.0% to Frontier at 71.8%. Three of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 87.7% of the time; SkyWest Airlines manages 79.3%. Sample sizes sit next to every figure, because a two-point gap across 408 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| American Airlinesthin sample | 1 | 100.0% | — | 0.00% | A+ |
| Delta Air Lines | 648 | 87.7% | 70 min | 0.93% | A+ |
| United Airlines (this page) | 3,421 | 85.7% | 57 min | 0.20% | A+ |
| SkyWest Airlines | 408 | 79.3% | 77 min | 0.49% | B+ |
| Spirit Airlinesthin sample | 333 | 78.9% | 71 min | 1.50% | B |
| Frontier Airlinesthin sample | 336 | 71.8% | 60 min | 0.89% | C+ |
Delta leads SkyWest by 8 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Flight by flight
United flight numbers on IAH to LAX
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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 16 points, against 8 points between the best and worst carrier.
- 5am–8am745 flights93.9%
- 8am–11am365 flights89.0%
- 11am–2pm365 flights89.0%
- 2pm–5pm719 flights85.5%
- 5pm–8pm375 flights81.6%
- 8pm–5am852 flights77.6%
Scale runs 70% to 100%.
Book the early departure. Flights leaving between 5am–8am arrive on time 93.9% of the time, against 77.6% for the overnight window. That is 16 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 852 flights scheduled in it.
Across the year
United on IAH to LAX through the year
June is the worst month at 79.9% on time, 13 points below August, the best at 92.8%. 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 303 flights.
Across the week, Wednesday is the strongest day at 90.0% on time and Saturday the weakest at 80.9%, a spread of 9 points.
Arrival by arrival
How late United on IAH to LAX runs when it is late
United on IAH to LAX often beats the schedule: 1,141 of 3,411 completed flights, 33%, arrived 15 minutes or more early. The 488 late arrivals split 192 under half an hour, 149 between 30 and 60 minutes, and 147 an hour or more.
- 15+ min early1,141 flights33.5%
- Within 15 min1,782 flights52.2%
- 15–29 min late192 flights5.6%
- 30–59 min late149 flights4.4%
- 1–2 hours late100 flights2.9%
- 2+ hours late47 flights1.4%
Scale runs 0% to 100%.
Share of 3,411 completed flights by arrival against schedule.
A late pushback is often recovered here: of 564 departures that left 15 minutes late or more, 193 still arrived on time. 117 flights left on time and still arrived late.
The worst days
Worst days for United on IAH to LAX
The latest arrival of the period was on 7 March 2026, 11 hours 29 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). On three of the five worst days the largest share was filed as a late-arriving aircraft.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 7 March 2026 | 11 hours 29 minutes | Carrier |
| 28 October 2025 | 7 hours 14 minutes | Carrier |
| 26 September 2025 | 5 hours 29 minutes | Late-arriving aircraft |
| 3 June 2026 | 4 hours 32 minutes | Late-arriving aircraft |
| 28 August 2026 | 4 hours 31 minutes | Late-arriving aircraft |
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 28,000 reported delay minutes.
- 42%Carrier
- 34%Late-arriving aircraft
- 18%National Airspace System
- 6%Extreme weather
The largest share of delay minutes, 42%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 12,000 of the 28,000 delay minutes reported here. The split is drawn from 27,786 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 93.9% on time here.
Cancellations are rare at 0.20%, 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 stage length
What a delay here costs
Badly late arrivals are rare here: only 4.3% 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 1,379 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 return leg runs 87.4% on time across 3,420 flights, within 2 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 3,421 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 IAH to LAX
Put together: the calendar is the biggest lever here, not the carrier or the hour. August runs 92.8% on time and June 79.9%, a swing of 13 points. If the dates move at all, move them out of June before you think about anything else. 3,411 completed flights over 12 months sit behind that.
Related
Where to go next
- IAH to LAX, every carrier
- United on LAX to IAH, the return leg
- Delta Air Lines on IAH to LAX87.7%
- SkyWest Airlines on IAH to LAX79.3%
- Spirit Airlines on IAH to LAX78.9%
- Frontier Airlines on IAH to LAX71.8%
- United Airlines network-wide record
- George Bush Intercontinental (IAH) delay statistics
- Los Angeles International (LAX) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
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.