Carrier route record
DLLAS→SEA
Delta Air Lines · Las Vegas to Seattle
- 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 LAS to SEA earns an A+. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 10 points better than the national rate of 77.6%. When something does go wrong the average delay runs an hour and a half. That rests on 1,738 flights. The strongest carrier on the route with a full sample, Alaska Airlines, flew 2,638 at 82.8% on time.
Set against the rest of the country, Delta's LAS to SEA record is 10 points better than the US average of 77.6%. That gap is worth roughly 100 fewer late arrivals for every thousand flights.
Key figures
On time
87.6%
Arrivals under 15 minutes late, of 1,722 completed flights
Avg delay
87 min
Across delayed arrivals only, not all flights
Cancelled
0.86%
National rate is 1.81%
Whole route
82.3%
Every carrier on LAS to SEA, 5,649 flights
These figures cover 1,738 flights between July 2025 and June 2026. The median arrival is 13 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 LAS to SEA
Delta flew 1,738 of the 5,649 flights on LAS to SEA, about 31% of it. Its 87.6% on time is 5 points better than the route as a whole, which runs 82.3%. Ranked by on-time rate it is number two of six carriers on the route, where the range runs from Spirit at 88.4% to Southwest at 71.0%. 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 82.8% of the time; Southwest Airlines manages 71.0%. Sample sizes sit next to every figure, because a two-point gap across 977 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Spirit Airlinesthin sample | 43 | 88.4% | 47 min | 0.00% | A+ |
| Delta Air Lines (this page) | 1,738 | 87.6% | 87 min | 0.86% | A+ |
| SkyWest Airlinesthin sample | 7 | 85.7% | 59 min | 0.00% | A+ |
| Alaska Airlines | 2,638 | 82.8% | 64 min | 1.25% | B |
| Frontier Airlinesthin sample | 246 | 82.2% | 48 min | 0.81% | B+ |
| Southwest Airlines | 977 | 71.0% | 45 min | 0.31% | C+ |
Alaska leads Southwest by 12 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Flight by flight
Delta flight numbers on LAS to SEA
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 18 points, against 12 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am367 flights95.6%
- 8am–11am93 flights92.5%
- 11am–2pm429 flights90.8%
- 2pm–5pm514 flights84.4%
- 5pm–8pm330 flights78.0%
- 8pm–5am5 flights—
Scale runs 70% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 95.6% of the time, against 78.0% for the evening window. That is 18 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 2pm–5pm window is the busiest, with 514 flights scheduled in it.
Across the year
Delta on LAS to SEA through the year
August is the worst month at 83.3% on time, 8 points below February, the best at 91.6%. 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. March was the busiest month here, with 151 flights.
Across the week, Saturday is the strongest day at 91.6% on time and Friday the weakest at 81.5%. 10 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 46% of the 19,000 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.
- 46%Carrier
- 44%Late-arriving aircraft
- 9%National Airspace System
- 2%Extreme weather
44% 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 19,000 reported delay minutes here, that single category outweighs weather by 23 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 18,595 reported delay minutes.
The largest share of delay minutes, 46%, 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 8,557 of the 19,000 delay minutes reported here.
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 4.7% 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 83.6% on time across 1,738 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 1,738 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 LAS to SEA
Put together: avoid the 5pm–8pm departure. It runs 78.0% on time against 95.6% for the 5am–8am slot, and that 18 points is the largest single thing you control here. Alaska Airlines is the strongest operator if the fares are close. 1,722 completed flights over 12 months sit behind that.
Related
Where to go next
- LAS to SEA, every carrier
- Delta on SEA to LAS, the return leg
- Alaska Airlines on LAS to SEA82.8%
- Frontier Airlines on LAS to SEA82.2%
- Southwest Airlines on LAS to SEA71.0%
- Delta Air Lines network-wide record
- Harry Reid International (LAS) delay statistics
- Seattle-Tacoma International (SEA) delay statistics
- Same route, different airline: where the carrier you pick matters most
- Why the first flight of the morning is statistically safest
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.