Flight number record
AS 478
Alaska Airlines · Seattle to Las Vegas
- Route
- SEA → LAS
- Departs
- 20:10
- Flights
- 314
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 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+. Close to three flights in four arrive on time by the DOT's definition, 4 points worse than the national rate of 77.3%. The late ones land about 50 minutes behind schedule. That rests on 314 flights, with a median arrival 1 minute late.
The national on-time rate over the same period is 77.3%, so AS 478 runs 4 points behind the country as a whole. Across a thousand flights that is about 40 extra late arrivals.
Key figures
On time
73.3%
Arrivals under 15 minutes late, of 311 completed flights
Avg delay
50 min
Across delayed arrivals only, not all flights
Cancelled
0.64%
National rate is 1.89%
1 hour+ late
6.8%
National rate is 8.3%
These figures cover 314 flights between September 2025 and August 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.
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Schedule
When AS 478 flies
AS 478 flies SEA to LAS without a single fixed slot. Its most common scheduled departure was 20:10, used on 55 of 314 flights, with 18:32 (43 flights) and 20:20 (34 flights) next.
- Departs 20:1055 flights17.5%
- Departs 18:3243 flights13.7%
- Departs 20:2034 flights10.8%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 20:10 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.1%, and AS 478 runs 3 points better at 73.3%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.
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Against the route
AS 478 next to SEA to LAS
Every carrier on SEA to LAS combined arrived on time 77.6% of the time across 5,620 flights, so AS 478 is 4 points behind it. Alaska flew 2,612 flights on the same city pair under all its flight numbers, including this one, and those ran 78.7% on time. Across its whole network Alaska Airlines managed 79.7%, which this flight trails by 6 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| AS 478thin sample | 314 | 73.3% | 50 min | 0.64% | C+ |
| All Alaska Airlines on SEA–LAS | 2,612 | 78.7% | 48 min | 0.84% | B+ |
| All carriers on SEA–LAS | 5,620 | 77.6% | 56 min | 0.93% | B+ |
| Alaska Airlines, whole network | 309,844 | 79.7% | 52 min | 1.20% | 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 2026 at 64.6%, a swing of 19 points on roughly 63 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 202530 flights66.7%
- Oct–Dec 202579 flights68.8%
- Jan–Mar 202679 flights75.9%
- Apr–Jun 202678 flights83.1%
- Jul–Sep 202648 flights64.6%
Scale runs 55% to 90%.
By weekday, AS 478 did best on Wednesday at 82.9% on time and worst on Sunday at 66.7%. Each day rests on about 45 flights, so a gap of 16 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late AS 478 runs when it is late
The 83 late arrivals split 33 under half an hour, 29 between 30 and 60 minutes, and 21 an hour or more.
- 15+ min early57 flights18.3%
- Within 15 min171 flights55.0%
- 15–29 min late33 flights10.6%
- 30–59 min late29 flights9.3%
- 1–2 hours late15 flights4.8%
- 2+ hours late6 flights1.9%
Scale runs 0% to 100%.
Share of 311 completed flights by arrival against schedule.
A late pushback is often recovered here: of 90 departures that left 15 minutes late or more, 27 still arrived on time. In the other direction, 20 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at LAS.
The worst days
Worst days for AS 478
The latest arrival of the period was on 10 August 2026, 5 hours 38 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The five worst days are spread across August, March, October and May, with no single month standing out.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 10 August 2026 | 5 hours 38 minutes | Late-arriving aircraft |
| 13 March 2026 | 2 hours 45 minutes | Extreme weather |
| 24 October 2025 | 2 hours 24 minutes | Carrier |
| 31 May 2026 | 2 hours 17 minutes | Late-arriving aircraft |
| 3 May 2026 | 2 hours 13 minutes | National Airspace System |
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 4,145 reported delay minutes.
- 36%Late-arriving aircraft
- 35%National Airspace System
- 23%Carrier
- 6%Extreme weather
36% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 4,145 reported delay minutes here, that single category outweighs weather by 6 to one. The split is drawn from 4,145 delay minutes reported on AS 478.
Cancellations are rare at 0.64%, below the national 1.89% 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 routes
What a delay on this flight costs
6.8% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about 50 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.
The same number turns up on two other city pairs in the data, including SEA to BUR (11) and BUR to SEA (11), but none flew often enough under AS 478 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to SEA to LAS only.
One caution: this is a thin sample. 314 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, read AS 478 as 73.3% on time with 0.64% cancelled over 314 flights. Those are rates from the past twelve months, not a forecast for any particular day.
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 route91.1%
- Delta Air Lines 2905 on the same route82.9%
- Delta Air Lines 2880 on the same route80.1%
- Delta Air Lines 2949 on the same route78.9%
- Alaska Airlines 738 on the same route78.3%
- Alaska Airlines 704 on the same route84.2%
- 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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.