Alaska AirlinesAS
Flights AS607 06:02 daily · AS654 12:12 daily · AS575 15:14 daily · AS594 19:59 Mo Th Fr Su
live
Direct flights from Ontario (ONT) to Seattle (SEA): 22 nonstop departures observed each week across 4 airlines. 50% of the last 8 operated flights arrived within 15 minutes of schedule. The median arrival is 35 minutes late. No cancellations were recorded across the 8 tracked flights. The nonstop covers 1,540 km, an estimated 2 hours 28 minutes in the air. Measured by Pro Flight Search from live flight boards at Ontario and Seattle. Updated 21 September 2026 at 11:23 UTC.
ONT
Ontario
busy · +23
SEA
Seattle
busy · +23
1,540 km · ~2h 28m est.
Runs rough · 4 airlines · 22x weekly · nonstop
50% on time
of the last 8 operated ONT → SEA flights arrived within 15 minutes
Median arrival delay is +35 min. 0 of 8 tracked legs cancelled in the sample. Will a delayed flight be cancelled? →
Median arrival+35 minacross the last 8 operated legs
Flight time~2h 28mestimated from route distance
Weekly departures22x4 direct airlines on the leg
The week
scheduled departures · origin local time06121824
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Alaska AirlinesDelta Air LinesFrontier AirlinesSouthwest Airlines
Each mark is a scheduled departure at its origin-local time, observed operating in the last 7 days. Today is highlighted.
Who flies it
observed on the boards · 7 daysHistory
operated legs · board outcomesActual board outcomes rather than schedules, paired departure and arrival per flight and day.
Full board history, day by day →
Airports right now
live boardsWeather lens
Current conditions put the pressure at SEA: 30% odds of a 15+ minute delay and around +3 min expected when it bites, measured from this route's own weather-matched delay history. See live delays → · Weather risk by airport →
next sweep in 120s
How the Ontario to Seattle route actually runs
Pro Flight Search records official board updates for nonstop ONT to SEA flights through the day: schedules, estimates, gate pushes and actual departures. The verdict above comes from operated flights, so it reflects what this route does rather than what the timetable promises.
Planning around a delay? Live airport delays · Weather delay risk map · Will a delayed flight be cancelled? · Do planes make up time in the air? · How we measure
Cite this data
Journalists, bloggers, and researchers may cite this page with attribution and a link to Pro Flight Search.
Suggested citation
Pro Flight Search — Ontario (ONT) to Seattle (SEA) route reliability, measured from operated flights on official airport boards.
Canonical URL
How we measure this →
https://proflightsearch.com/search-flights/ONT-SEA
ONT to SEA questions
Is ONT–SEA running on time right now?
Mostly on schedule. Both endpoints currently score the same, route health score 70/100. The airports section above carries the live status and delay window at both ends.
Morning or evening flight on ONT–SEA?
Operators schedule morning departures around 06:00 and evening departures around 17:44 from ONT. Earlier flights typically land before destination-airport delays accumulate later in the day; check the SEA delay card to confirm conditions when you'd arrive.
How long is the flight from ONT to SEA?
Great-circle distance is 1,540 km. With typical jet cruise speed plus taxi, climb and descent, expect roughly 139–162 min gate-to-gate on this route.
How often does ONT–SEA fly?
4 carriers operate this route, around 53 flights a week between them. Compare carrier days and times in the airline list above.
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