SEA → ONT: cancellations & delays
Over Jan 2023 - Apr 2026, 1.0% of Seattle–Tacoma International Airport (SEA) to Ontario International Airport (ONT) flights were cancelled and 18.6% arrived at least 15 minutes late, across 8,116 flights, flown by AS, OO, DL, F9. Cancellations peak in January.
Check today's live SEA departures →Airport pages: Seattle–Tacoma International Airport (SEA) · Ontario International Airport (ONT)
Rates are historical averages from U.S. DOT (BTS) on-time records; a specific flight's live estimate can differ with weather and the day's disruptions.