Carrier route record
ASFLL→SEA
Alaska Airlines · Fort Lauderdale to Seattle
- Flights
- 462
- Period
- July 2025 to June 2026
- Share of route
- 56%
- Carriers
- 2
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Alaska Airlines.
Alaska on FLL to SEA draws a C. About one flight in three arrives at least 15 minutes late, and the typical late arrival is about an hour behind schedule. Build slack into anything you connect to. That rests on 462 flights, with a median arrival 3 minutes late.
The national on-time rate over the same period is 77.6%, so Alaska on FLL to SEA runs 11 points behind the country as a whole. Across a thousand flights that is about 111 extra late arrivals.
Key figures
On time
66.5%
Arrivals under 15 minutes late, of 448 completed flights
Avg delay
56 min
Across delayed arrivals only, not all flights
Cancelled
1.30%
National rate is 1.81%
Whole route
69.7%
Every carrier on FLL to SEA, 826 flights
These figures cover 462 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.
Carrier by carrier
Alaska against every carrier on FLL to SEA
Alaska flew 462 of the 826 flights on FLL to SEA, most of the route. Its 66.5% on time is 3 points worse than the route as a whole, which runs 69.7%. Ranked by on-time rate it is last of two carriers on the route, where the range runs from Delta at 73.8% to Alaska at 66.5%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
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 Linesthin sample | 364 | 73.8% | 79 min | 1.65% | C |
| Alaska Airlines (this page) | 462 | 66.5% | 56 min | 1.30% | C |
Flight by flight
Alaska flight numbers on FLL to SEA
Departure window
When Alaska 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 462 flights.
- 5am–8am109 flights68.3%
- 8am–11am—
- 11am–2pm—
- 2pm–5pm—
- 5pm–8pm353 flights66.0%
- 8pm–5am—
Scale runs 60% to 75%. Rows with fewer than 30 flights show a dash.
The 5am–8am window is the strongest at 68.3% on time. The full set of windows spans 2 points.
Across the year
Alaska on FLL to SEA through the year
August is the worst month at 45.2% on time, 45 points below May, the best at 90.0%. 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. December was the busiest month here, with 62 flights.
Across the week, Tuesday is the strongest day at 75.4% on time and Sunday the weakest at 48.4%. 27 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 8,405 reported delay minutes.
- 39%Late-arriving aircraft
- 34%National Airspace System
- 22%Carrier
- 5%Extreme weather
- 0%Security
39% 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 8,405 reported delay minutes here, that single category outweighs weather by 8 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 8,405 reported delay minutes.
34% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 2,852 minutes out of 8,405, against a national NAS share of 21%.
Cancellations sit at 1.30% against a national 1.81%, which is ordinary. Diversions add another 1.73%.
Connections and stage length
What a delay here costs
7.8% 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 about an hour, which a normal layover absorbs.
At 2,717 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 81.4% on time across 462 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. 462 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 FLL to SEA
Put together: treat all of this as provisional. 462 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 66.5% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 448 completed flights over 12 months sit behind that.
Related
Where to go next
- FLL to SEA, every carrier
- Alaska on SEA to FLL, the return leg
- Delta Air Lines on FLL to SEA73.8%
- Alaska Airlines network-wide record
- Fort Lauderdale-Hollywood International (FLL) delay statistics
- Seattle-Tacoma International (SEA) delay statistics
- Why the first flight of the morning is statistically safest
- Worst months to fly in the US, ranked by the data
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.