ONT (Ontario) to DEN (Denver) flights arrive on time 82% of the time. The most reliable airline on this route is United Airlines at 85%. The average delay is 71 minutes. Delays on this route are most often caused by the incoming plane arriving late.
Source: Bureau of Transportation Statistics. Updated May 2026.ONT → DEN
ONT (Ontario) to DEN (Denver)
ONT → DEN on-time performance by month
24
25
JanFebMarAprMayJunJulAugSepOctNovDec
Worse
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This route is on time most of the time. About 82% of flights arrive on schedule.
Delays on this route are most often caused by the incoming plane arriving late.
Accurate?
United Airlines edges out Frontier Airlines on this route — 85% vs 77% on time.
Airline Comparison
United Airlines leads at 85% on time; Frontier Airlines trails at 77%.
Accurate?
Good to know
Departing from ONT
82% on timeTSA is currently ~13 min. Best time: 4 AM (about 5 min).
Arriving at DEN
78% on timeWhen flights into DEN are late, the average delay is 67 minutes. Build buffer if you have ground plans.
If connecting at DEN: TSA is ~13 min right now. Allow at least 60 minutes for a domestic connection.
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Data last updated May 2026. Source: Bureau of Transportation Statistics.