Carrier route record
ASSEA→KOA
Alaska Airlines · Seattle to Kailua-Kona
- Flights
- 1,056
- Period
- July 2025 to June 2026
- Share of route
- 74%
- Carriers
- 2
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Alaska Airlines.
Alaska on SEA to KOA sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 7 points worse than the national rate of 77.6%. The late ones land roughly 50 minutes behind schedule. That rests on 1,056 flights, with a median arrival 2 minutes early.
The national on-time rate over the same period is 77.6%, so Alaska on SEA to KOA runs 7 points behind the country as a whole. Across a thousand flights that is about 67 extra late arrivals.
Key figures
On time
70.9%
Arrivals under 15 minutes late, of 1,033 completed flights
Avg delay
51 min
Across delayed arrivals only, not all flights
Cancelled
0.95%
National rate is 1.81%
Whole route
72.8%
Every carrier on SEA to KOA, 1,421 flights
These figures cover 1,056 flights between July 2025 and June 2026. The median arrival is 2 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 KOA
Alaska flew 1,056 of the 1,421 flights on SEA to KOA, most of the route. Its 70.9% on time is 2 points worse than the route as a whole, which runs 72.8%. Ranked by on-time rate it is last of two carriers on the route, where the range runs from Delta at 78.5% to Alaska at 70.9%.
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines | 365 | 78.5% | 51 min | 1.64% | B |
| Alaska Airlines (this page) | 1,056 | 70.9% | 51 min | 0.95% | C+ |
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 19 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am1 flights—
- 8am–11am315 flights69.7%
- 11am–2pm309 flights68.8%
- 2pm–5pm109 flights87.2%
- 5pm–8pm322 flights68.3%
- 8pm–5am—
Scale runs 60% to 95%. Rows with fewer than 30 flights show a dash.
The best window here is not the first bank but the 2pm–5pm slot at 87.2% on time, ahead of 5pm–8pm at 68.3%. Where the curve peaks mid-day rather than at dawn, the constraint is usually congestion at one end rather than the aircraft's own rotation. The 5pm–8pm window is the busiest, with 322 flights scheduled in it.
Across the year
Alaska on SEA to KOA through the year
July is the worst month at 50.0% on time, 45 points below April, the best at 95.1%. 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. January was the busiest month here, with 93 flights.
Across the week, Monday is the strongest day at 76.4% on time and Friday the weakest at 64.6%. 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 15,000 reported delay minutes.
- 40%Carrier
- 31%Late-arriving aircraft
- 27%National Airspace System
- 2%Extreme weather
The largest share of delay minutes, 40%, 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 6,150 of the 15,000 delay minutes reported here. The split is drawn from 15,453 reported delay minutes.
Cancellations sit at 0.95% against a national 1.81%, which is ordinary. Diversions add another 1.23%.
Connections and stage length
What a delay here costs
7.5% 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 50 minutes, which a normal layover absorbs.
At 2,688 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The return leg is a different operation and performs like one: it runs 85.7% on time across 1,057 flights, 15 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 15 points of difference.
One caution: this is a thin sample. 1,056 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 Alaska on SEA to KOA
Put together: treat all of this as provisional. 1,056 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 70.9% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 1,033 completed flights over 12 months sit behind that.
Related
Where to go next
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.