AS571 SeattleSEA · 11:29 OntarioONT · 14:16
AS571 by Alaska Airlines flies from Seattle (SEA) to Ontario (ONT) for the Mon, Sep 21 departure.
departs SEA · 1 min late
board checked 11m ago · checking again in 45s
Where the minutes go
last 5 operations · gate push → arrivalThe bar is how late it left the gate; the ring is where it actually arrived. Board clocks, not estimates.
The last 30 days
arrival outcome per operationmedian arrival −8 min · 0 cancelled · 5 operations tracked
The route today
live boardsWeather lens
Delay & cancellation outlook for this flight
Measured, 90-day sampleConditions at SEA and ONT are near their clear-air norm right now, so this reflects the route's recent baseline rather than a weather penalty. For this route and airline, under conditions like today's, over the last 90 days.
Pro Flight Search tracking, 90 days · the weather × delay correlation study → · live weather risk by airport →
When it flies
scheduled departuresEach mark is a scheduled departure at its origin-local time. Today is highlighted.
Other Seattle to Ontario flights today
same route · Alaska AirlinesIf AS571 is cancelled, these are the other Alaska Airlines nonstop flights from Seattle to Ontario on the same day, with scheduled departure times in SEA local time. Most flights posting a delay still operate — rebooking usually only beats a very large posted delay. Every airline on this route →
How AS571 actually runs
Pro Flight Search has tracked every published board update for AS571 across the SEA and ONT boards: schedule changes, gate pushes and actual clocks. Usually lands ~5 min early. Based on 5 confirmed landings · 5/5 within 15 min of schedule.
The verdict above is that record speaking, so it reflects how AS571 operates rather than what the timetable promises. Numbers refresh as new flights operate.
How this operation is measured
Board log
scheduled → actual, per operationAircraft
Recent tails: N968AK, N284AK, N520AS, N290AK.
Board clocks recorded as SEA and ONT published them.
Planning around AS571? Will a delayed flight be cancelled? · Do planes make up time in the air? · How we measure
Journalists, bloggers, and researchers may cite this page with attribution and a link to Pro Flight Search.
Pro Flight Search — AS571 Seattle to Ontario on-time performance, measured from the SEA and ONT airport boards.
https://proflightsearch.com/flight/AS571
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