Carrier route record

NKLAX→IAH

Spirit Airlines · Los Angeles to Houston

Flights: 455
Period: July 2025 to June 2026
Share of route: 9%
Carriers: 5

Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Spirit Airlines.

Spirit on LAX to IAH lands a B, level with the national rate of 77.6%. Roughly one flight in four arrives 15 minutes late or worse, and those flights are late by an hour and a half on average. That is a workable record, not a spotless one. That rests on 455 flights. The strongest carrier on the route with a full sample, United Airlines, flew 3,415 at 87.1% on time.

United Airlines is the most reliable of the three carriers covered here at 87.1% on time across 3,415 flights.

On time

77.5%

Arrivals under 15 minutes late, of 448 completed flights

Avg delay

83 min

Across delayed arrivals only, not all flights

Cancelled

1.32%

National rate is 1.81%

Whole route

84.6%

Every carrier on LAX to IAH, 5,255 flights

These figures cover 455 flights between July 2025 and June 2026. Beyond the headline rate, 8.7% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.

Carrier by carrier

Spirit against every carrier on LAX to IAH

Spirit flew 455 of the 5,255 flights on LAX to IAH, about 9% of it. Its 77.5% on time is 7 points worse than the route as a whole, which runs 84.6%. Ranked by on-time rate it is number four of five carriers on the route, where the range runs from United at 87.1% to Frontier at 68.2%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The three carriers here are closely matched: 5 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.

On-time performance by carrier on LAX to IAH
Airline	Flights	On time	Avg delay	Cancelled	Grade
United Airlines	3,415	87.1%	55 min	0.26%	A+
Delta Air Lines	645	86.1%	73 min	1.09%	A
SkyWest Airlines	408	82.0%	68 min	0.49%	B+
Spirit Airlines (this page)	455	77.5%	83 min	1.32%	B
Frontier Airlinesthin sample	332	68.2%	71 min	2.11%	C

No carrier stands out. United tops the table at 87.1%, 5 points clear of the bottom, which is inside the range this kind of sample moves year to year.

Departure window

When Spirit runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 23 points, against 5 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am51 flights87.8%
8am–11am15 flights—
11am–2pm18 flights—
2pm–5pm33 flights64.5%
5pm–8pm191 flights72.5%
8pm–5am147 flights82.2%

Scale runs 55% to 95%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 87.8% of the time, against 64.5% for the afternoon window. That is 23 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5pm–8pm window is the busiest, with 191 flights scheduled in it.

Across the year

Spirit on LAX to IAH through the year

Jul–Sep 2025184 flights89.6%
Oct–Dec 2025153 flights66.4%
Jan–Mar 202689 flights71.3%
Apr–Jun 202629 flights—

Scale runs 60% to 95%. Rows with fewer than 30 flights show a dash.

Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 77.5% on time across 455 flights.

Spirit on LAX to IAH did not run the same all year. Its best quarter was Jul–Sep 2025 at 89.6% on time and its weakest Oct–Dec 2025 at 66.4%, a swing of 23 points on roughly 152 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.

Across the week, Tuesday is the strongest day at 83.1% on time and Sunday the weakest at 66.2%. 17 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Spirit runs late on this route

One category carries most of the weight here. Late-arriving aircraft accounts for 47% of the 8,427 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.

Late-arriving aircraft
47%
Carrier
28%
National Airspace System
25%
Extreme weather
0%

47% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 8,427 reported delay minutes here, that single category outweighs weather by 47 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 8,427 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 87.8% on time here.

Cancellations sit at 1.32% against a national 1.81%, which is ordinary. Diversions add another 0.22%.

Connections and stage length

What a delay here costs

8.7% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last an hour and a half, 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. 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 return leg is a different operation and performs like one: it runs 83.6% on time across 458 flights, 6 points above this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 6 points of difference.

One caution: this is a thin sample. 455 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 Spirit on LAX to IAH

Put together: treat all of this as provisional. 455 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 77.5% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 448 completed flights over 12 months sit behind that.

Where to go next

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.

Key figures