Carrier route record

NKIAH→LAX

Spirit Airlines · Houston to Los Angeles

Flights: 333
Period: September 2025 to August 2026
Share of route: 6%
Carriers: 6

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

Spirit on IAH to LAX lands a B, 2 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That rests on 333 flights. The strongest carrier on the route with a full sample, Delta Air Lines, flew 648 at 87.7% on time.

Delta Air Lines is the most reliable of the three carriers covered here at 87.7% on time across 648 flights.

On time

78.9%

Arrivals under 15 minutes late, of 327 completed flights

Avg delay

71 min

Across delayed arrivals only, not all flights

Cancelled

1.50%

National rate is 1.89%

Whole route

84.1%

Every carrier on IAH to LAX, 5,147 flights

These figures cover 333 flights between September 2025 and August 2026. The median arrival is 13 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

Spirit against every carrier on IAH to LAX

Spirit flew 333 of the 5,147 flights on IAH to LAX, about 6% of it. Its 78.9% on time is 5 points worse than the route as a whole, which runs 84.1%. Ranked by on-time rate it is number five of six carriers on the route, where the range runs from American at 100.0% to Frontier at 71.8%. Two 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.

On-time performance by carrier on IAH to LAX
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 Airlines (this page)thin 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.

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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 12 points, against 8 points between the best and worst carrier.

5am–8am78 flights87.0%
8am–11am2 flights—
11am–2pm—
2pm–5pm115 flights78.9%
5pm–8pm13 flights—
8pm–5am125 flights75.2%

Scale runs 65% to 90%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 87.0% of the time, against 75.2% for the overnight window. That is 12 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 125 flights scheduled in it.

Across the year

Spirit on IAH to LAX through the year

Jul–Sep 202560 flights81.4%
Oct–Dec 2025154 flights81.7%
Jan–Mar 202689 flights75.0%
Apr–Jun 202630 flights—

Scale runs 65% to 85%. 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 78.9% on time across 333 flights.

Quarter by quarter Spirit on IAH to LAX held fairly steady: 81.4% in Jul–Sep 2025, 81.7% in Oct–Dec 2025 and 75.0% in Jan–Mar 2026. A spread of 7 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.

Across the week, Tuesday is the strongest day at 91.7% on time and Thursday the weakest at 63.0%, a spread of 29 points.

Arrival by arrival

How late Spirit on IAH to LAX runs when it is late

Spirit on IAH to LAX often beats the schedule: 152 of 327 completed flights, 46%, arrived 15 minutes or more early. The 69 late arrivals split 24 under half an hour, 24 between 30 and 60 minutes, and 21 an hour or more.

15+ min early152 flights46.5%
Within 15 min106 flights32.4%
15–29 min late24 flights7.3%
30–59 min late24 flights7.3%
1–2 hours late10 flights3.1%
2+ hours late11 flights3.4%

Scale runs 0% to 100%.

Share of 327 completed flights by arrival against schedule.

27 of 91 late departures made up the time and arrived on time, 30% of them. Only 5 left on time and still arrived late.

The worst days

Worst days for Spirit on IAH to LAX

The latest arrival of the period was on 11 November 2025, 9 hours 43 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on three of the five worst days.

The latest arrivals of Spirit on IAH to LAX in the period
Date	Arrived late by	Largest filed cause
11 November 2025	9 hours 43 minutes	Carrier
26 October 2025	9 hours 34 minutes	Late-arriving aircraft
7 March 2026	3 hours 13 minutes	Extreme weather
17 November 2025	2 hours 54 minutes	Carrier
7 December 2025	2 hours 48 minutes	Carrier

Delay causes

Why Spirit runs late on this route

Carrier accounts for 44% of the 4,916 delay minutes carriers reported here, and the remaining four split what is left.

Carrier
44%
Late-arriving aircraft
33%
National Airspace System
19%
Extreme weather
4%

The largest share of delay minutes, 44%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 2,171 of the 4,916 delay minutes reported here. The split is drawn from 4,916 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 87.0% on time here.

Cancellations sit at 1.50% against a national 1.89%, which is ordinary. Diversions add another 0.30%.

Connections and stage length

What a delay here costs

6.4% 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 a little over 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 is a different operation and performs like one: it runs 73.0% on time across 331 flights, 6 points below 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. 333 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 IAH to LAX

Put together: treat all of this as provisional. 333 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 78.9% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 327 completed flights over 12 months sit behind that.

Where to go next

Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated 22 October 2026; recomputed monthly. How this data is collected.

Key figures