Flight number record
AS 517
Alaska Airlines · Fort Lauderdale to Seattle
- Route
- FLL → SEA
- Departs
- 18:30
- Flights
- 317
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s AS 517, check with Alaska Airlines.
AS 517 draws a C+. About one flight in three arrives at least 15 minutes late, and the typical late arrival is roughly 45 minutes behind schedule. Build slack into anything you connect to. That rests on 317 flights, with a median arrival 3 minutes late.
The national on-time rate over the same period is 77.3%, so AS 517 runs 11 points behind the country as a whole. Across a thousand flights that is about 105 extra late arrivals.
Key figures
On time
66.8%
Arrivals under 15 minutes late, of 310 completed flights
Avg delay
46 min
Across delayed arrivals only, not all flights
Cancelled
0.95%
National rate is 1.89%
1 hour+ late
5.8%
National rate is 8.3%
These figures cover 317 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 517 flies
AS 517 flies FLL to SEA without a single fixed slot. Its most common scheduled departure was 18:30, used on 70 of 317 flights, with 18:23 (47 flights) and 17:54 (35 flights) next.
- Departs 18:3070 flights22.1%
- Departs 18:2347 flights14.8%
- Departs 17:5435 flights11.0%
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 18:30 departure sits in the 5pm–8pm window. Across every US flight scheduled in that window the on-time rate is 68.0%, and AS 517 runs level with that at 66.8%. 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 517 next to FLL to SEA
Every carrier on FLL to SEA combined arrived on time 73.3% of the time across 826 flights, so AS 517 is 7 points behind it. Across its whole network Alaska Airlines managed 79.7%, which this flight trails by 13 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| AS 517thin sample | 317 | 66.8% | 46 min | 0.95% | C+ |
| All Alaska Airlines on FLL–SEA | 462 | 68.4% | 50 min | 1.08% | C |
| All carriers on FLL–SEA | 826 | 73.3% | 53 min | 1.21% | C |
| Alaska Airlines, whole network | 309,844 | 79.7% | 52 min | 1.20% | B |
Across the year
AS 517 quarter by quarter
AS 517 did not run the same all year. Its best quarter was Apr–Jun 2026 at 80.9% on time and its weakest Jan–Mar 2026 at 48.8%, a swing of 32 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 flights70.0%
- Oct–Dec 202589 flights58.1%
- Jan–Mar 202645 flights48.8%
- Apr–Jun 202691 flights80.9%
- Jul–Sep 202662 flights69.4%
Scale runs 40% to 85%.
By weekday, AS 517 did best on Thursday at 80.4% on time and worst on Sunday at 46.7%. Each day rests on about 45 flights, so a gap of 34 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late AS 517 runs when it is late
The 103 late arrivals split 45 under half an hour, 40 between 30 and 60 minutes, and 18 an hour or more.
- 15+ min early68 flights21.9%
- Within 15 min139 flights44.8%
- 15–29 min late45 flights14.5%
- 30–59 min late40 flights12.9%
- 1–2 hours late10 flights3.2%
- 2+ hours late8 flights2.6%
Scale runs 0% to 100%.
Share of 310 completed flights by arrival against schedule.
17 of 76 late departures made up the time and arrived on time, 22% of them. In the other direction, 44 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 SEA.
The worst days
Worst days for AS 517
The latest arrival of the period was on 22 December 2025, 5 hours 12 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). On four of the five worst days the largest share was filed as a late-arriving aircraft.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 22 December 2025 | 5 hours 12 minutes | Carrier |
| 12 February 2026 | 3 hours 9 minutes | Late-arriving aircraft |
| 13 March 2026 | 2 hours 48 minutes | Late-arriving aircraft |
| 9 November 2025 | 2 hours 22 minutes | Late-arriving aircraft |
| 16 October 2025 | 2 hours 16 minutes | Late-arriving aircraft |
Delay causes
Why AS 517 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 4,748 reported delay minutes.
- 35%Late-arriving aircraft
- 34%National Airspace System
- 23%Carrier
- 8%Extreme weather
35% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 4,748 reported delay minutes here, that single category outweighs weather by 5 to one. The split is drawn from 4,748 delay minutes reported on AS 517.
Cancellations sit at 0.95% against a national 1.89%, which is ordinary. Diversions add another 1.26%.
Connections and routes
What a delay on this flight costs
5.8% 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 roughly 45 minutes, 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 same number turns up on one other city pair in the data, including SEA to FLL (28), but none flew often enough under AS 517 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to FLL to SEA only.
One caution: this is a thin sample. 317 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 517
For a booking, AS 517 is one of the weaker ways to fly FLL to SEA: 7 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
- FLL to SEA, every carrier and departure
- SEA to FLL, the return direction
- Delta Air Lines 356 on the same route81.9%
- Fort Lauderdale-Hollywood International (FLL) delay statistics
- Seattle-Tacoma International (SEA) 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.