Route reliability record
MCI→LAS
Kansas City to Las Vegas
- Flights
- 1,987
- Period
- July 2025 to June 2026
- Distance
- 1,139 mi
- Carriers
- 3
This route 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 about 50 minutes on average. That is a workable record, not a spotless one. That rests on 1,987 MCI to LAS flights, with a median arrival 5 minutes early.
Best time to fly MCI to LAS: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 94.8% of the time and Wednesday flights 91.0%, against 81.0% for the route overall.
The US average over the same twelve months is 77.6%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
81.0%
Arrivals under 15 minutes late, of 1,973 completed flights
Avg delay
49 min
Across delayed arrivals only, not all flights
Cancelled
0.50%
National rate is 1.81%
Best carrier
Southwest
80.2% on time across 1,712 flights
These figures cover 1,987 flights between July 2025 and June 2026. The median arrival is 5 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
Which airline is most reliable on MCI to LAS
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.
| 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 | 1,712 | 80.2% | 47 min | 0.23% | B+ |
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 35 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–8am463 flights94.8%
- 8am–11am305 flights90.2%
- 11am–2pm305 flights82.2%
- 2pm–5pm412 flights73.2%
- 5pm–8pm291 flights74.6%
- 8pm–5am211 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 94.8% 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 463 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 15 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
Delays peak in April, when the on-time rate falls to 72.6%. January is the strongest month at 87.3%. Moving a flexible trip across that boundary buys 15 points. March was the busiest month here, with 184 flights.
Across the week, Wednesday is the strongest day at 91.0% on time and Monday the weakest at 76.1%. 15 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. Late-arriving aircraft accounts for 49% of the 18,000 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.
- 49%Late-arriving aircraft
- 26%National Airspace System
- 18%Carrier
- 5%Extreme weather
- 2%Security
49% 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 18,000 reported delay minutes here, that single category outweighs weather by 10 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 18,452 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 94.8% on time here.
Cancellations are rare at 0.50%, 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 actually costs
Badly late arrivals are rare here: only 4.5% 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 76.6% on time across 1,978 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.
The sample behind these figures is 1,987 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 LAS after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. January runs 87.3% on time and April 72.6%, a swing of 15 points. If the dates move at all, move them out of April before you think about anything else. 1,973 completed flights over 12 months sit behind that.
Common questions
MCI to LAS questions
How often is MCI to LAS delayed?
About one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 19.0% of the 1,987 flights in this analysis, against 22.4% nationally. Delayed flights are late by about 50 minutes on average.
How reliable is MCI to LAS compared with the rest of the country?
81.0% of flights arrive on time here against a national 77.6%, a difference of 3 points in its favour. That is worth a B+ on this site's grading scale.
What time of day has the fewest delays on MCI to LAS?
The 5am–8am departure window is the strongest at 94.8% on time. The 8pm–5am window is the weakest at 59.5%, 35 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 April delays on MCI to LAS?
April is the weakest month at 72.6% on time, compared with 87.3% in January. Across the year that is 15 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
- LAS to MCI — the return legseparate record
- Kansas City International (MCI) delay statistics
- Harry Reid International (LAS) delay statistics
- Spirit Airlines on MCI to LAS85.7%
- Southwest Airlines on MCI to LAS80.2%
- MCI to DEN, a related route76.1%
- LAX to LAS, a related route76.5%
- MCI to ORD, a related route74.7%
- American Airlines on-time record100.0%
- Spirit Airlines on-time record85.7%
- Southwest Airlines on-time record80.2%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. MCI to LAS and LAS to MCI are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
Embed MCI to LAS’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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.