Route reliability record
LAX→IAH
Los Angeles to Houston
- Flights
- 5,143
- Period
- September 2025 to August 2026
- Distance
- 1,379 mi
- Carriers
- 5
This route earns a B+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 7 points better than the national rate of 77.3%. When something does go wrong the average delay runs about an hour. That rests on 5,143 LAX to IAH flights, of which United Airlines flew 3,420 at 87.4% on time.
Best time to fly LAX to IAH: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 94.9% of the time and Wednesday flights 87.1%, against 84.6% for the route overall.
United Airlines is the most reliable of the three carriers covered here at 87.4% on time across 3,420 flights.
Key figures
On time
84.6%
Arrivals under 15 minutes late, of 5,107 completed flights
Avg delay
61 min
Across delayed arrivals only, not all flights
Cancelled
0.47%
National rate is 1.89%
Best carrier
United
87.4% on time across 3,420 flights
These figures cover 5,143 flights between September 2025 and August 2026. The median arrival is 7 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
Which airline is most reliable on LAX to IAH
The choice of carrier is not cosmetic here. United Airlines arrives on time 87.4% of the time; SkyWest Airlines manages 81.2%. 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 |
|---|---|---|---|---|---|
| United Airlines | 3,420 | 87.4% | 52 min | 0.18% | A+ |
| Delta Air Lines | 648 | 84.8% | 70 min | 0.93% | B+ |
| SkyWest Airlines | 408 | 81.2% | 70 min | 0.49% | B+ |
| Spirit Airlinesthin sample | 331 | 73.0% | 73 min | 1.51% | C |
| Frontier Airlinesthin sample | 336 | 70.6% | 74 min | 1.49% | C |
United leads SkyWest by 6 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Flight by flight
Flights on LAX to IAH
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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Best ways to make this trip
The most reliable ways to fly Los Angeles to Houston
Every airline on this route and on the routes between nearby airports, ranked by how often a scheduled flight actually operated and arrived on time. 2 of the top 5 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. SNA → IAHSanta Ana to Houston | United Airlines | 88.4% | 88.4% | 0.00% | 8am–11am, Thu | — |
| 2. LAX → IAHLos Angeles to Houston | United Airlines | 87.2% | 87.4% | 0.18% | 5am–8am, Wed | UA 654 05:45 |
| 3. LAX → IAHLos Angeles to Houston | Delta Air Lines | 84.0% | 84.8% | 0.93% | 8am–11am, Mon | DL 1143 09:40 |
| 4. LAX → IAHLos Angeles to Houston | SkyWest Airlines | 80.8% | 81.2% | 0.49% | 8am–11am, Tue | — |
| 5. LAX → HOULos Angeles to Houston | Southwest Airlines | 69.3% | 69.4% | 0.17% | 5am–8am, Sat | — |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 17 points, against 6 points between the best and worst carrier.
- 5am–8am684 flights94.9%
- 8am–11am1,239 flights88.2%
- 11am–2pm1,026 flights77.8%
- 2pm–5pm648 flights79.6%
- 5pm–8pm908 flights81.0%
- 8pm–5am638 flights87.7%
Scale runs 70% to 100%.
The weak window here is the middle of the day, not the evening: 11am–2pm runs 77.8% on time against 94.9% for 5am–8am. 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 8am–11am window is the busiest, with 1,239 flights scheduled in it.
Explore
Filter LAX to IAH by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On LAX to IAH, the best departure window is 5am–8am at 94.9% on time and the worst is 11am–2pm at 77.8%, a wide gap of 17.1 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am94.9%
- 8–11am88.2%
- 11am–2pm77.8%
- 2–5pm79.6%
- 5–8pm81.0%
- 8pm–5am87.7%
best all US flightsScale 60% to 100%.
Across the year
When delays peak on this route
This route's year swings by 15 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
September is the best month on the calendar at 92.3% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. October was the busiest month here, with 493 flights.
Across the week, Wednesday is the strongest day at 87.1% on time and Sunday the weakest at 82.4%, a spread of 5 points.
Delay causes
Why this route gets delayed
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 48,000 reported delay minutes.
- 37%Late-arriving aircraft
- 36%Carrier
- 25%National Airspace System
- 2%Extreme weather
37% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 48,000 reported delay minutes here, that single category outweighs weather by 24 to one. The split is drawn from 47,620 reported delay minutes.
The largest share of delay minutes, 36%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 17,000 of the 48,000 delay minutes reported here.
Cancellations are rare at 0.47%, 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 actually costs
5.0% of arrivals land an hour or more late, close to the national 8.3%, so 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.
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 84.1% on time across 5,147 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 5,143 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.
Work out the risk of missing a connection in IAH after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 92.3% on time and November 77.4%, a swing of 15 points. If the dates move at all, move them out of November before you think about anything else. 5,107 completed flights over 12 months sit behind that.
Common questions
LAX to IAH questions
How often is LAX to IAH delayed?
Roughly one flight in six arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 15.4% of the 5,143 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on LAX to IAH?
United Airlines leads at 87.4% on time across 3,420 flights. SkyWest Airlines is at the other end on 81.2%, a gap of 6 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on LAX to IAH?
The 5am–8am departure window is the strongest at 94.9% on time. The 11am–2pm window is the weakest at 77.8%, 17 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are November delays on LAX to IAH?
November is the weakest month at 77.4% on time, compared with 92.3% in September. Across the year that is 15 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- IAH to LAX — the return legseparate record
- Los Angeles International (LAX) delay statistics
- George Bush Intercontinental (IAH) delay statistics
- United Airlines on LAX to IAH87.4%
- Delta Air Lines on LAX to IAH84.8%
- SkyWest Airlines on LAX to IAH81.2%
- Spirit Airlines on LAX to IAH73.0%
- Frontier Airlines on LAX to IAH70.6%
- LAX to SFO, a related route60.1%
- ORD to IAH, a related route76.0%
- LAX to JFK, a related route77.5%
- United Airlines on-time record87.4%
- Delta Air Lines on-time record84.8%
- SkyWest Airlines on-time record81.2%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
Direction matters. LAX to IAH and IAH to LAX are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.