Carrier route record

WNMCI→LAS

Southwest Airlines · Kansas City to Las Vegas

Flights: 1,712
Period: July 2025 to June 2026
Share of route: 86%
Carriers: 3

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

Southwest on MCI to LAS lands a B+, 3 points better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by roughly 45 minutes on average. That is a workable record, not a spotless one. That rests on 1,712 flights, with a median arrival 4 minutes early.

The US average over the same twelve months is 77.6%, so there is little to separate Southwest on MCI to LAS from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.

On time

80.2%

Arrivals under 15 minutes late, of 1,706 completed flights

Avg delay

47 min

Across delayed arrivals only, not all flights

Cancelled

0.23%

National rate is 1.81%

Whole route

81.0%

Every carrier on MCI to LAS, 1,987 flights

These figures cover 1,712 flights between July 2025 and June 2026. The median arrival is 4 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.

Carrier by carrier

Southwest against every carrier on MCI to LAS

Southwest flew 1,712 of the 1,987 flights on MCI to LAS, most of the route. Its 80.2% on time is about level with the route as a whole at 81.0%. Ranked by on-time rate it is last of three carriers on the route, where the range runs from American at 100.0% to Southwest at 80.2%. Two 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 MCI to LAS
Airline	Flights	On time	Avg delay	Cancelled	Grade
American Airlinesthin sample	2	100.0%	—	0.00%	A+
Spirit Airlinesthin sample	273	85.7%	66 min	2.20%	A
Southwest Airlines (this page)	1,712	80.2%	47 min	0.23%	B+

Departure window

When Southwest runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 36 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–8am369 flights95.4%
8am–11am305 flights90.2%
11am–2pm258 flights82.9%
2pm–5pm346 flights70.7%
5pm–8pm228 flights72.6%
8pm–5am206 flights59.5%

Scale runs 50% to 100%. Rows with fewer than 30 flights show a dash.

The 8pm–5am window is where this operation falls apart: 59.5% on time, against 95.4% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 5am–8am window is the busiest, with 369 flights scheduled in it.

Across the year

Southwest on MCI to LAS through the year

Darker means more delays. Figures are on-time percentages.January best, April worst

Delays peak in April, when the on-time rate falls to 71.8%. January is the strongest month at 86.5%. Moving a flexible trip across that boundary buys 15 points. June was the busiest month here, with 158 flights.

Across the week, Wednesday is the strongest day at 90.7% on time and Monday the weakest at 74.3%. 16 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Southwest runs late on this route

One category carries most of the weight here. Late-arriving aircraft accounts for 53% of the 16,000 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
53%
National Airspace System
21%
Carrier
19%
Extreme weather
4%
Security
3%

53% 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 16,000 reported delay minutes here, that single category outweighs weather by 15 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 15,934 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 95.4% on time here.

Cancellations are rare at 0.23%, below the national 1.81% 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 costs

Badly late arrivals are rare here: only 4.3% land an hour or more behind schedule, against 8.1% 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 1,139 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 75.1% on time across 1,705 flights, 5 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 5 points of difference.

The sample behind these figures is 1,712 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.

What to do with this

Booking Southwest on MCI to LAS

Put together: the calendar is the biggest lever here, not the carrier or the hour. January runs 86.5% on time and April 71.8%, a swing of 15 points. If the dates move at all, move them out of April before you think about anything else. 1,706 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