Ontario International Airport (ONT) delays & on-time performance
Ontario, California · 25 nonstop destinations · 9 airlines · Aug 2025 – Jul 2026
No FAA-reported ground stops or delays at ONT right now. Individual flights can still be delayed by the airline; check with your airline for your flight.
On-time arrivals
82%
arrived < 15 min late
Cancelled
0.9%
225 flights
Avg arrival delay
13 min
68 min when late
Departed on time
81%
avg taxi-out 14 min
Figures cover 25,854 departures from ONT; on-time is measured at arrival. Arrivals into ONT were on time 78% of the time.
Key facts
- Flights departing Ontario International Airport (ONT) arrived on time 82% of the time in Aug 2025 – Jul 2026, better than the 78% national average.
- 0.9% were cancelled, and 6% arrived an hour or more late.
- Delta Air Lines was the most punctual airline here (91% on time); Frontier Airlines was the least (76%).
- Departures scheduled around 5am did best (96% on time); around 6pm did worst (68%).
- The largest source of delay minutes was late-arriving aircraft (43%).
Most delayed routes from ONT
Lowest on-time arrival rates among regularly flown routes.
- SFO · San Francisco62%1,309 flts
- HOU · Houston65%362 flts
- DAL · Dallas74%399 flts
- LAS · Las Vegas77%2,476 flts
- DFW · Dallas/Fort Worth79%2,297 flts
- DEN · Denver81%2,643 flts
- PHX · Phoenix82%3,027 flts
- IAH · Houston85%561 flts
- SJC · San Jose86%1,319 flts
- SMF · Sacramento86%2,114 flts
Most reliable routes from ONT
Highest on-time arrival rates among regularly flown routes.
- SLC · Salt Lake City92%1,239 flts
- PDX · Portland90%565 flts
- MDW · Chicago90%360 flts
- ATL · Atlanta89%937 flts
- HNL · Honolulu87%423 flts
- OAK · Oakland86%1,471 flts
- SEA · Seattle86%2,505 flts
- SMF · Sacramento86%2,114 flts
- SJC · San Jose86%1,319 flts
- IAH · Houston85%561 flts
Best airline at ONT
Departures from this airport, ranked by on-time arrival.
| Airline | On time | Cancelled | Avg delay | Routes | Flights |
|---|---|---|---|---|---|
| Delta Air Lines | 91% | 1.4% | 9 min | 3 | 1,865 |
| Envoy Air | 89% | 0.0% | 4 min | 1 | 45 |
| SkyWest Airlines | 88% | 0.4% | 10 min | 8 | 1,724 |
| Alaska Airlines | 85% | 1.4% | 9 min | 3 | 2,067 |
| American Airlines | 82% | 2.0% | 19 min | 3 | 3,608 |
| Southwest Airlines | 81% | 0.4% | 10 min | 13 | 11,662 |
| United Airlines | 80% | 0.5% | 16 min | 4 | 2,460 |
| Frontier Airlines | 76% | 1.3% | 20 min | 8 | 2,258 |
| JetBlue | 70% | 1.8% | 59 min | 1 | 165 |
Best time to fly out of ONT
On-time arrival rate by scheduled departure hour (local time).
- 5am96%1,565 flts
- 6am92%3,779 flts
- 7am90%1,532 flts
- 8am87%1,420 flts
- 9am87%1,239 flts
- 10am83%1,582 flts
- 11am83%1,386 flts
- 12pm78%1,711 flts
- 1pm76%1,951 flts
- 2pm68%1,065 flts
- 3pm75%1,147 flts
- 4pm76%1,352 flts
- 5pm80%1,293 flts
- 6pm68%1,269 flts
- 7pm74%876 flts
- 8pm69%672 flts
- 9pm72%540 flts
- 10pm84%806 flts
- 11pm81%594 flts
Monthly trend
Why departures were late
- Late-arriving aircraft43%
- Airline (crew, maintenance, cleaning, fueling)34%
- Air traffic control & airport congestion21%
- Extreme weather2%
- Security0%
Data: U.S. DOT Bureau of Transportation Statistics, Aug 2025 – Jul 2026 (12 months). Latest month published by BTS: July 2026. How we calculate this.