ONT → ORD: cancellations & delays
Over Jan 2023 - Apr 2026, 0.7% of Ontario International Airport (ONT) to Chicago O'Hare International Airport (ORD) flights were cancelled and 20.5% arrived at least 15 minutes late, across 270 flights, flown by UA. Cancellations peak in March.
Check today's live ONT departures →Airport pages: Ontario International Airport (ONT) · Chicago O'Hare International Airport (ORD)
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.