Route reliability record
IAH→LAX
Houston to Los Angeles
- Flights
- 5,147
- Period
- September 2025 to August 2026
- Distance
- 1,379 mi
- Carriers
- 6
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 5,147 IAH to LAX flights, of which Delta Air Lines flew 648 at 87.7% on time.
Best time to fly IAH to LAX: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 93.1% of the time and Wednesday flights 88.9%, against 84.1% for the route overall.
Delta Air Lines is the most reliable of the three carriers covered here at 87.7% on time across 648 flights.
Key figures
On time
84.1%
Arrivals under 15 minutes late, of 5,119 completed flights
Avg delay
62 min
Across delayed arrivals only, not all flights
Cancelled
0.45%
National rate is 1.89%
Best carrier
Delta
87.7% on time across 648 flights
These figures cover 5,147 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.
Fare search by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Carrier by carrier
Which airline is most reliable on IAH to LAX
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 | 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
Flights on IAH to LAX
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.
- Delta 121607:0093.1% · 365 flights
- United 246012:4089.0% · 365 flights
- United 174316:3183.3% · 360 flights
- United 260007:2091.3% · 355 flights
- United 46909:5389.0% · 349 flights
- Frontier 175516:0271.9% · 334 flights
- United 209519:5076.7% · 323 flights
- United 194514:2088.4% · 286 flights
- United 243106:0095.4% · 261 flights
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Best ways to make this trip
The most reliable ways to fly Houston to Los Angeles
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. IAH → SNAHouston to Santa Ana | United Airlines | 88.5% | 88.5% | 0.00% | 8am–11am, Tue | UA 1383 09:30 |
| 2. IAH → LAXHouston to Los Angeles | Delta Air Lines | 86.9% | 87.7% | 0.93% | 5am–8am, Wed | DL 1216 07:00 |
| 3. IAH → LAXHouston to Los Angeles | United Airlines | 85.5% | 85.7% | 0.20% | 5am–8am, Wed | UA 2431 06:00 |
| 4. IAH → LAXHouston to Los Angeles | SkyWest Airlines | 78.9% | 79.3% | 0.49% | 2pm–5pm, Sat | — |
| 5. HOU → LAXHouston to Los Angeles | Southwest Airlines | 73.5% | 73.6% | 0.17% | 5am–8am, Fri | — |
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 15 points, against 8 points between the best and worst carrier.
- 5am–8am1,215 flights93.1%
- 8am–11am415 flights86.7%
- 11am–2pm434 flights85.7%
- 2pm–5pm1,304 flights82.7%
- 5pm–8pm631 flights78.3%
- 8pm–5am1,148 flights77.8%
Scale runs 70% to 100%.
Book the early departure. Flights leaving between 5am–8am arrive on time 93.1% of the time, against 77.8% for the overnight window. That is 15 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 2pm–5pm window is the busiest, with 1,304 flights scheduled in it.
Explore
Filter IAH to LAX 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 IAH to LAX, the best departure window is 5am–8am at 93.1% on time and the worst is 8pm–5am at 77.8%, a wide gap of 15.3 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am93.1%
- 8–11am86.7%
- 11am–2pm85.7%
- 2–5pm82.7%
- 5–8pm78.3%
- 8pm–5am77.8%
best all US flightsScale 60% to 100%.
Across the year
When delays peak on this route
Twelve months, one bar each, drawn from the same 5,147 flights. The strip shows how much of this route's record is set by the calendar rather than by the operation.
June is the worst month at 79.2% on time, 10 points below August, the best at 89.4%. 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. October was the busiest month here, with 493 flights.
Across the week, Wednesday is the strongest day at 88.9% on time and Saturday the weakest at 80.5%, a spread of 8 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 50,000 reported delay minutes.
- 41%Carrier
- 36%Late-arriving aircraft
- 18%National Airspace System
- 6%Extreme weather
- 0%Security
36% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 50,000 reported delay minutes here, that single category outweighs weather by 6 to one. The split is drawn from 50,377 reported delay minutes.
The largest share of delay minutes, 41%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 20,000 of the 50,000 delay minutes reported here.
Cancellations are rare at 0.45%, 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
Badly late arrivals are rare here: only 4.9% 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 84.6% on time across 5,143 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 5,147 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 LAX after this flight
What to do with this
Booking this route
Put together: avoid the 8pm–5am departure. It runs 77.8% on time against 93.1% for the 5am–8am slot, and that 15 points is the largest single thing you control here. Delta Air Lines is the strongest operator if the fares are close. 5,119 completed flights over 12 months sit behind that.
Common questions
IAH to LAX questions
How often is IAH to LAX delayed?
About 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 15.9% of the 5,147 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on IAH to LAX?
Delta Air Lines leads at 87.7% on time across 648 flights. SkyWest Airlines is at the other end on 79.3%, a gap of 8 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 IAH to LAX?
The 5am–8am departure window is the strongest at 93.1% on time. The 8pm–5am window is the weakest at 77.8%, 15 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 June delays on IAH to LAX?
June is the weakest month at 79.2% on time, compared with 89.4% in August. Across the year that is 10 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
- LAX to IAH — the return legseparate record
- George Bush Intercontinental (IAH) delay statistics
- Los Angeles International (LAX) delay statistics
- Delta Air Lines on IAH to LAX87.7%
- United Airlines on IAH to LAX85.7%
- SkyWest Airlines on IAH to LAX79.3%
- Spirit Airlines on IAH to LAX78.9%
- Frontier Airlines on IAH to LAX71.8%
- IAH to ORD, a related route75.1%
- SFO to LAX, a related route70.9%
- IAH to DFW, a related route76.4%
- American Airlines on-time record100.0%
- Delta Air Lines on-time record87.7%
- United Airlines on-time record85.7%
- 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. IAH to LAX and LAX to IAH are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
Embed IAH to LAX’s on-time badge on your site
Paste this into a web page. The badge shows the current on-time rate, cancellation rate and grade, and updates every month. Preview it, or build a badge for another route or airport.
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.