Carrier route record
DLKOA→SEA
Delta Air Lines · Kailua-Kona to Seattle
- Flights
- 365
- Period
- July 2025 to June 2026
- Share of route
- 26%
- Carriers
- 2
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Delta Air Lines.
Delta on KOA 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 14 points better than the national rate of 77.6%. When something does go wrong the average delay runs roughly 45 minutes. That rests on 365 flights, with a median arrival 16 minutes early.
Set against the rest of the country, Delta's KOA to SEA record is 14 points better than the US average of 77.6%. That gap is worth roughly 139 fewer late arrivals for every thousand flights.
Key figures
On time
91.5%
Arrivals under 15 minutes late, of 355 completed flights
Avg delay
46 min
Across delayed arrivals only, not all flights
Cancelled
2.74%
National rate is 1.81%
Whole route
87.2%
Every carrier on KOA to SEA, 1,422 flights
These figures cover 365 flights between July 2025 and June 2026. The median arrival is 16 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 KOA to SEA
Delta flew 365 of the 1,422 flights on KOA to SEA, about 26% of it. Its 91.5% on time is 4 points better than the route as a whole, which runs 87.2%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from Delta at 91.5% to Alaska at 85.7%.
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 (this page) | 365 | 91.5% | 46 min | 2.74% | A |
| Alaska Airlines | 1,057 | 85.7% | 60 min | 1.99% | A |
Flight by flight
Delta flight numbers on KOA to SEA
Departure window
When Delta runs best on this route
Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 365 flights.
The overnight block holds up unusually well at 91.5% on time across 365 flights. Red-eyes fly into empty airspace and empty gates, and they are the first rotation of the aircraft's day rather than the last. The 8pm–5am window is the busiest, with 365 flights scheduled in it.
Across the year
Delta on KOA to SEA through the year
January is the weak month at 77.4% on time, against 100.0% in July. 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. January was the busiest month here, with 31 flights.
Across the week, Tuesday is the strongest day at 98.0% on time and Wednesday the weakest at 84.3%. 14 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 64% of the 1,393 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.
- 64%Carrier
- 23%National Airspace System
- 13%Late-arriving aircraft
The largest share of delay minutes, 64%, 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 895 of the 1,393 delay minutes reported here. The split is drawn from 1,393 reported delay minutes.
Cancellations run at 2.74%, against 1.81% nationally. That is roughly one flight in 40 cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.
Connections and stage length
What a delay here costs
Badly late arrivals are rare here: only 2.5% 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.
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 78.5% on time across 365 flights, 13 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 13 points of difference.
One caution: this is a thin sample. 365 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 Delta on KOA to SEA
Put together: treat all of this as provisional. 365 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 91.5% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 355 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.