Carrier route record

NKIAH→LAS

Spirit Airlines · Houston to Las Vegas

Flights: 527
Period: July 2025 to June 2026
Share of route: 15%
Carriers: 3

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

Spirit on IAH to LAS lands a B, 4 points better than the national rate of 77.6%. About one flight in six arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 527 flights, with a median arrival 11 minutes early.

Set against the rest of the country, Spirit's IAH to LAS record is 4 points better than the US average of 77.6%. That gap is worth roughly 43 fewer late arrivals for every thousand flights.

On time

81.9%

Arrivals under 15 minutes late, of 515 completed flights

Avg delay

78 min

Across delayed arrivals only, not all flights

Cancelled

2.09%

National rate is 1.81%

Whole route

82.4%

Every carrier on IAH to LAS, 3,457 flights

These figures cover 527 flights between July 2025 and June 2026. Beyond the headline rate, 8.0% 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 IAH to LAS

Spirit flew 527 of the 3,457 flights on IAH to LAS, about 15% of it. Its 81.9% on time is about level with the route as a whole at 82.4%. Ranked by on-time rate it is number two of three carriers on the route, where the range runs from United at 83.9% to Frontier at 71.7%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.

Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.

On-time performance by carrier on IAH to LAS
Airline	Flights	On time	Avg delay	Cancelled	Grade
United Airlines	2,602	83.9%	59 min	0.38%	B+
Spirit Airlines (this page)	527	81.9%	78 min	2.09%	B
Frontier Airlinesthin sample	328	71.7%	126 min	2.13%	C

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 half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am89 flights88.8%
8am–11am164 flights81.9%
11am–2pm—
2pm–5pm84 flights82.1%
5pm–8pm32 flights65.6%
8pm–5am158 flights81.3%

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 88.8% of the time, against 65.6% for the evening 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 8am–11am window is the busiest, with 164 flights scheduled in it.

Across the year

Spirit on IAH to LAS through the year

Darker means more delays. Figures are on-time percentages.September best, November worst

September is the best month on the calendar at 93.2% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. August was the busiest month here, with 65 flights.

Across the week, Wednesday is the strongest day at 91.3% on time and Thursday the weakest at 77.0%. 14 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Spirit 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 7,214 reported delay minutes.

Late-arriving aircraft
38%
Carrier
36%
National Airspace System
23%
Extreme weather
3%
Security
0%

38% 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 7,214 reported delay minutes here, that single category outweighs weather by 14 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 7,214 reported delay minutes.

The largest share of delay minutes, 36%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 2,566 of the 7,214 delay minutes reported here.

Cancellations sit at 2.09% against a national 1.81%, which is ordinary. Diversions add another 0.19%.

Connections and stage length

What a delay here costs

8.0% 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 a little over an hour, which a normal layover absorbs.

The 1,222 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 77.6% on time across 526 flights, 4 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 4 points of difference.

One caution: this is a thin sample. 527 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 LAS

Put together: treat all of this as provisional. 527 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 81.9% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 515 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