Airports › Ontario (ONT) › September 2025
Airport month · September 2025
Ontario International in September 2025
BTS: A flight is counted as on time if it arrived less than 15 minutes after its scheduled time. Only carriers with at least 0.5 percent of domestic scheduled passenger revenue report.
In September 2025, reporting carriers scheduled 2,177 domestic departures from Ontario International (ONT). 84.4% left less than 15 minutes late and 84.2% reached their destination on time; 0.5% were cancelled.
Nationally that month, 83.1% of flights departed on time and 82.8% arrived on time, so ONT departures were 1.3 points above the national departure figure.
A year earlier, in September 2024, the airport had 2,316 departures with 85.5% leaving on time: a change of −1.1 points, with flights down 6%.
Flights arriving at ONT that month were on time 81.1% of the time (2,175 scheduled arrivals).
Of the delay minutes that carriers assigned to a BTS cause category that month, air carrier 37%, late-arriving aircraft 36% and national aviation system 25%.
- On time 84.2%
- Arrived 15+ minutes late 15.1%
- Cancelled 0.5%
- Diverted 0.1%
September 2025 against a year earlier, the airport's year and the nation
| Measure | Sep 2025 | Sep 2024 | ONT, 12 months to Jul 2026 | All reported flights, Sep 2025 |
|---|---|---|---|---|
| Departed on time | 84.4% | 85.5% | 80.3% | 83.1% |
| Arrived on time | 84.2% | 86.4% | 81.2% | 82.8% |
| Cancelled | 0.5% | 0.3% | 0.9% | 0.5% |
| Average departure delay (late minutes only) | 12.7 min | 10.4 min | 13.7 min | 12.2 min |
| Scheduled departures a day | 73 | 77 | 71 | 18,748 |
| Scheduled departures | 2,177 | 2,316 | 25,854 | 562,439 |
Airlines that month
| Reporting carrier | Flights | Share | On time | Avg arrival delay | Cancelled |
|---|---|---|---|---|---|
| WN Southwest Airlines | 966 | 44% | 86.2% | 2.3 min | 0.1% |
| AA American Airlines | 261 | 12% | 79.7% | 5.2 min | 3.1% |
| UA United Airlines | 232 | 11% | 79.7% | 5.2 min | 0.0% |
| F9 Frontier Airlines | 201 | 9% | 73.6% | 7.4 min | 0.0% |
| DL Delta Air Lines | 168 | 8% | 95.2% | -7.3 min | 0.0% |
| OO SkyWest Airlines | 166 | 8% | 89.8% | 4.9 min | 0.6% |
| AS Alaska Airlines | 153 | 7% | 84.3% | 0.5 min | 0.7% |
| B6 JetBlue Airways | 30 | 1% | 73.3% | 34.2 min | 0.0% |
Busiest routes that month
| Route | Cities | Flights | On time | Avg arrival delay | Cancelled |
|---|---|---|---|---|---|
| ONT–DEN | Ontario to Denver | 237 | 81.0% | 4.2 min | 0.0% |
| ONT–PHX | Ontario to Phoenix | 227 | 83.7% | 4.5 min | 2.2% |
| ONT–SEA | Ontario to Seattle | 213 | 87.3% | -0.5 min | 0.5% |
| ONT–LAS | Ontario to Las Vegas | 201 | 76.6% | 11.5 min | 0.0% |
| ONT–DFW | Ontario to Dallas/Fort Worth | 183 | 73.8% | 6.9 min | 2.7% |
| ONT–SMF | Ontario to Sacramento | 177 | 93.2% | -4.3 min | 0.0% |
| ONT–OAK | Ontario to Oakland | 133 | 91.0% | -2.9 min | 0.0% |
| ONT–SLC | Ontario to Salt Lake City | 110 | 90.9% | 4.9 min | 0.0% |
| ONT–SFO | Ontario to San Francisco | 108 | 64.8% | 15.8 min | 0.0% |
| ONT–SJC | Ontario to San Jose | 107 | 86.0% | 3.1 min | 0.0% |
| ONT–ATL | Ontario to Atlanta | 77 | 97.4% | -12.7 min | 0.0% |
| ONT–PDX | Ontario to Portland | 61 | 91.8% | -5.3 min | 0.0% |
By scheduled departure hour
Delay causes
Questions and answers
How many flights left ONT on time in September 2025?
84.4% of 2,177 scheduled domestic departures left less than 15 minutes late, and 84.2% reached their destination on time. The national figures that month were 83.1% and 82.8%.
How does that compare with a year earlier?
In September 2024, 85.5% of 2,316 departures left on time and 0.3% were cancelled, against 84.4% and 0.5% in September 2025.
Provenance
Source: Bureau of Transportation Statistics, Reporting Carrier On-Time Performance, file for September 2025; public domain. Domestic scheduled flights by reporting carriers, totals and averages only. The site's data runs through July 2026. Full record for ONT · methodology · corrections.