SEA (Seattle) to ONT (Ontario) flights arrive on time 83% of the time. The most reliable airline on this route is SkyWest Airlines at 91%. The average delay is 49 minutes. Delays on this route are most often caused by the airline (crew, maintenance, or boarding).
Source: Bureau of Transportation Statistics. Updated March 2026.SEA → ONT
SEA (Seattle) to ONT (Ontario)
SEA → ONT on-time performance by month
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This route is on time most of the time. About 83% of flights arrive on schedule.
Delays on this route are most often caused by the airline (crew, maintenance, or boarding).
Accurate?
SkyWest Airlines edges out Frontier Airlines on this route — 91% vs 78% on time.
Airline Comparison
SkyWest Airlines leads at 91% on time; Frontier Airlines trails at 78%.
Accurate?
Good to know
Departing from SEA
82% on timeExpect ~19 min sitting on the taxiway after your gate pushes back. SEA has long runway queues.
TSA is currently ~5 min. Best time: 4 AM (about 5 min).
Arriving at ONT
82% on timeWhen flights into ONT are late, the average delay is 63 minutes. Build buffer if you have ground plans.
If connecting at ONT: TSA is ~5 min right now. Allow at least 60 minutes for a domestic connection.
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Data last updated March 2026. Source: Bureau of Transportation Statistics.