Flight number record
AS 478
Alaska Airlines · Seattle to Las Vegas
- Route
- SEA → LAS
- Departs
- 18:50
- Flights
- 326
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 2026, not live status. For today’s AS 478, check with Alaska Airlines.
AS 478 sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 5 points worse than the national rate of 77.6%. The late ones land roughly 45 minutes behind schedule. That rests on 326 flights, with a median arrival 1 minute late.
The national on-time rate over the same period is 77.6%, so AS 478 runs 5 points behind the country as a whole. Across a thousand flights that is about 49 extra late arrivals.
Key figures
On time
72.7%
Arrivals under 15 minutes late, of 322 completed flights
Avg delay
47 min
Across delayed arrivals only, not all flights
Cancelled
0.92%
National rate is 1.81%
1 hour+ late
6.2%
National rate is 8.1%
These figures cover 326 flights between July 2025 and June 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.
Schedule
When AS 478 flies
AS 478 flies SEA to LAS without a single fixed slot. Its most common scheduled departure was 18:50, used on 80 of 326 flights, with 20:10 (55 flights) and 20:20 (34 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 18:5080 flights24.5%
- Departs 20:1055 flights16.9%
- Departs 20:2034 flights10.4%
Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 18:50 departure sits in the 5pm–8pm window. Across every US flight scheduled in that window the on-time rate is 68.2%, and AS 478 runs 5 points better at 72.7%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.
Against the route
AS 478 next to SEA to LAS
Every carrier on SEA to LAS combined arrived on time 77.7% of the time across 5,650 flights, so AS 478 is 5 points behind it. Alaska flew 2,638 flights on the same city pair under all its flight numbers, including this one, and those ran 78.0% on time. Across its whole network Alaska Airlines managed 79.1%, which this flight trails by 6 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| AS 478thin sample | 326 | 72.7% | 47 min | 0.92% | C+ |
| All Alaska Airlines on SEA–LAS | 2,638 | 78.0% | 47 min | 0.91% | B+ |
| All carriers on SEA–LAS | 5,650 | 77.7% | 54 min | 0.83% | B+ |
| Alaska Airlines, whole network | 293,372 | 79.1% | 52 min | 1.28% | B |
Across the year
AS 478 quarter by quarter
AS 478 did not run the same all year. Its best quarter was Apr–Jun 2026 at 83.1% on time and its weakest Jul–Sep 2025 at 64.0%, a swing of 19 points on roughly 82 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
- Jul–Sep 202590 flights64.0%
- Oct–Dec 202579 flights68.8%
- Jan–Mar 202679 flights75.9%
- Apr–Jun 202678 flights83.1%
Scale runs 55% to 90%. Rows with fewer than 30 flights show a dash.
By weekday, AS 478 did best on Wednesday at 86.5% on time and worst on Sunday at 62.0%. Each day rests on about 47 flights, so a gap of 25 points is worth noticing but could still narrow in another year.
Delay causes
Why AS 478 runs late
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 4,156 reported delay minutes.
- 38%National Airspace System
- 37%Late-arriving aircraft
- 18%Carrier
- 6%Extreme weather
37% 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 4,156 reported delay minutes here, that single category outweighs weather by 6 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 4,156 delay minutes reported on AS 478.
Cancellations sit at 0.92% against a national 1.81%, which is ordinary. Diversions add another 0.31%.
Connections and routes
What a delay on this flight costs
6.2% 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.
Every one of the 326 flights under AS 478 in the data flew SEA to LAS. The number was not reused on any other city pair, which makes this a clean record of one route.
One caution: this is a thin sample. 326 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking AS 478
For a booking, AS 478 is one of the weaker ways to fly SEA to LAS: 5 points below the route as a whole. If the schedule allows, compare it with the other departures listed on the route page before settling on this one.
Related
Where to go next
- SEA to LAS, every carrier and departure
- LAS to SEA, the return direction
- Delta Air Lines 2922 on the same route91.4%
- Delta Air Lines 2905 on the same route86.1%
- Delta Air Lines 2880 on the same route80.4%
- Delta Air Lines 2949 on the same route81.0%
- Alaska Airlines 738 on the same route78.6%
- Alaska Airlines 658 on the same route80.6%
- Seattle-Tacoma International (SEA) delay statistics
- Harry Reid International (LAS) delay statistics
- Alaska Airlines on-time record
- Every Alaska Airlines flight number with a record
- The most and least reliable flight numbers in the US
- Why the first flight of the morning is statistically safest
A flight number here means Alaska Airlines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.
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.