Carrier route record
DLSEA→LAS
Delta Air Lines · Seattle to Las Vegas
- Flights
- 1,738
- Period
- July 2025 to June 2026
- Share of route
- 31%
- Carriers
- 6
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Delta Air Lines.
Delta on SEA to LAS lands a B+, 6 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 about an hour on average. That is a workable record, not a spotless one. That rests on 1,738 flights. The strongest carrier on the route with a full sample, Alaska Airlines, flew 2,638 at 78.0% on time.
Set against the rest of the country, Delta's SEA to LAS record is 6 points better than the US average of 77.6%. That gap is worth roughly 60 fewer late arrivals for every thousand flights.
Key figures
On time
83.6%
Arrivals under 15 minutes late, of 1,721 completed flights
Avg delay
56 min
Across delayed arrivals only, not all flights
Cancelled
0.86%
National rate is 1.81%
Whole route
77.7%
Every carrier on SEA to LAS, 5,650 flights
These figures cover 1,738 flights between July 2025 and June 2026. The median arrival is 8 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
Delta against every carrier on SEA to LAS
Delta flew 1,738 of the 5,650 flights on SEA to LAS, about 31% of it. Its 83.6% on time is 6 points better than the route as a whole, which runs 77.7%. Ranked by on-time rate it is number two 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. Alaska Airlines arrives on time 78.0% 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 (this page) | 1,738 | 83.6% | 56 min | 0.86% | B+ |
| Alaska Airlines | 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+ |
Alaska leads Southwest by 9 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Flight by flight
Delta flight numbers on SEA to LAS
Departure window
When Delta runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 16 points, against 9 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am365 flights91.4%
- 8am–11am348 flights88.1%
- 11am–2pm350 flights81.4%
- 2pm–5pm311 flights75.2%
- 5pm–8pm124 flights76.6%
- 8pm–5am240 flights82.4%
Scale runs 65% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 91.4% of the time, against 75.2% for the afternoon window. That is 16 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 365 flights scheduled in it.
Across the year
Delta on SEA to LAS through the year
December is the weak month at 76.0% on time, against 94.4% in August. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. March was the busiest month here, with 151 flights.
Across the week, Saturday is the strongest day at 86.0% on time and Friday the weakest at 81.0%. 5 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Delta runs late on this route
One category carries most of the weight here. Carrier accounts for 59% 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.
- 59%Carrier
- 24%National Airspace System
- 16%Late-arriving aircraft
- 0%Extreme weather
The largest share of delay minutes, 59%, 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 9,308 of the 16,000 delay minutes reported here. The split is drawn from 15,813 reported delay minutes.
Cancellations are rare at 0.86%, 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 4.5% 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 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 87.6% on time across 1,738 flights, 4 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 4 points of difference.
The sample behind these figures is 1,738 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 Delta on SEA to LAS
Put together: the calendar is the biggest lever here, not the carrier or the hour. August runs 94.4% on time and December 76.0%, a swing of 18 points. If the dates move at all, move them out of December before you think about anything else. 1,721 completed flights over 12 months sit behind that.
Related
Where to go next
- SEA to LAS, every carrier
- Delta on LAS to SEA, the return leg
- Alaska Airlines on SEA to LAS78.0%
- Southwest Airlines on SEA to LAS69.2%
- Frontier Airlines on SEA to LAS67.9%
- Delta Air Lines network-wide record
- Seattle-Tacoma International (SEA) delay statistics
- Harry Reid International (LAS) delay statistics
- The best time of day to fly, according to 7.04 million flight records
- Worst months to fly in the US, ranked by the data
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.