Carrier route record
ASSEA→LAS
Alaska Airlines · Seattle to Las Vegas
- Flights
- 2,638
- Period
- July 2025 to June 2026
- Share of route
- 47%
- Carriers
- 6
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Alaska Airlines.
Alaska on SEA to LAS lands a B+, level with the national rate of 77.6%. Roughly 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 2,638 flights. The strongest carrier on the route with a full sample, Delta Air Lines, flew 1,738 at 83.6% on time.
The US average over the same twelve months is 77.6%, so there is little to separate Alaska on SEA to LAS from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
78.0%
Arrivals under 15 minutes late, of 2,610 completed flights
Avg delay
47 min
Across delayed arrivals only, not all flights
Cancelled
0.91%
National rate is 1.81%
Whole route
77.7%
Every carrier on SEA to LAS, 5,650 flights
These figures cover 2,638 flights between July 2025 and June 2026. The median arrival is 3 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
Alaska against every carrier on SEA to LAS
Alaska flew 2,638 of the 5,650 flights on SEA to LAS, about 47% of it. Its 78.0% on time is about level with the route as a whole at 77.7%. Ranked by on-time rate it is number three of six carriers on the route, where the range runs from SkyWest at 100.0% to Spirit at 67.4%. Three 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 83.6% of the time; Southwest Airlines manages 69.2%. Sample sizes sit next to every figure, because a two-point gap across 976 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlinesthin sample | 9 | 100.0% | — | 0.00% | A+ |
| Delta Air Lines | 1,738 | 83.6% | 56 min | 0.86% | B+ |
| Alaska Airlines (this page) | 2,638 | 78.0% | 47 min | 0.91% | B+ |
| Southwest Airlines | 976 | 69.2% | 48 min | 0.51% | C+ |
| Frontier Airlinesthin sample | 246 | 67.9% | 128 min | 1.22% | C |
| Spirit Airlinesthin sample | 43 | 67.4% | 39 min | 0.00% | C+ |
The spread between Delta and Southwest is 14 points, wide enough that it should decide the booking. On a hundred trips that is 14 more arrivals inside the on-time window.
Flight by flight
Alaska flight numbers on SEA to LAS
Departure window
When Alaska runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 22 points, against 14 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am143 flights92.9%
- 8am–11am539 flights82.9%
- 11am–2pm466 flights81.2%
- 2pm–5pm507 flights77.7%
- 5pm–8pm642 flights72.0%
- 8pm–5am341 flights71.1%
Scale runs 65% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 92.9% of the time, against 71.1% for the overnight window. That is 22 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 642 flights scheduled in it.
Across the year
Alaska on SEA to LAS through the year
July is the worst month at 63.4% on time, 24 points below April, the best at 87.5%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. October was the busiest month here, with 241 flights.
Across the week, Tuesday is the strongest day at 84.5% on time and Monday the weakest at 72.5%. 12 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Alaska 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 27,000 reported delay minutes.
- 35%Late-arriving aircraft
- 33%National Airspace System
- 29%Carrier
- 3%Extreme weather
- 0%Security
35% 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 27,000 reported delay minutes here, that single category outweighs weather by 11 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 27,222 reported delay minutes.
33% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 8,885 minutes out of 27,000, against a national NAS share of 21%.
Cancellations sit at 0.91% against a national 1.81%, which is ordinary. Diversions add another 0.15%.
Connections and stage length
What a delay here costs
5.8% 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 roughly 45 minutes, which a normal layover absorbs.
The 867 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 82.8% on time across 2,638 flights, 5 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 5 points of difference.
The sample behind these figures is 2,638 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 Alaska on SEA to LAS
Put together: the calendar is the biggest lever here, not the carrier or the hour. April runs 87.5% on time and July 63.4%, a swing of 24 points. If the dates move at all, move them out of July before you think about anything else. 2,610 completed flights over 12 months sit behind that.
Related
Where to go next
- SEA to LAS, every carrier
- Alaska on LAS to SEA, the return leg
- Delta Air Lines on SEA to LAS83.6%
- Southwest Airlines on SEA to LAS69.2%
- Frontier Airlines on SEA to LAS67.9%
- Alaska Airlines network-wide record
- Seattle-Tacoma International (SEA) delay statistics
- Harry Reid International (LAS) delay statistics
- Why the first flight of the morning is statistically safest
- Same route, different airline: where the carrier you pick matters most
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.