Airports › Ontario (ONT) › May 2025
Airport month · May 2025
Ontario International in May 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 May 2025, reporting carriers scheduled 2,340 domestic departures from Ontario International (ONT). 82.4% left less than 15 minutes late and 82.3% reached their destination on time; 0.6% were cancelled.
Nationally that month, 76.7% of flights departed on time and 75.4% arrived on time, so ONT departures were 5.7 points above the national departure figure.
A year earlier, in May 2024, the airport had 2,259 departures with 77.9% leaving on time: a change of +4.5 points, with flights up 4%.
Flights arriving at ONT that month were on time 78.0% of the time (2,341 scheduled arrivals).
Of the delay minutes that carriers assigned to a BTS cause category that month, late-arriving aircraft 36%, air carrier 32% and national aviation system 28%.
- On time 82.3%
- Arrived 15+ minutes late 16.8%
- Cancelled 0.6%
- Diverted 0.3%
May 2025 against a year earlier, the airport's year and the nation
| Measure | May 2025 | May 2024 | ONT, 12 months to Jul 2026 | All reported flights, May 2025 |
|---|---|---|---|---|
| Departed on time | 82.4% | 77.9% | 80.3% | 76.7% |
| Arrived on time | 82.3% | 77.6% | 81.2% | 75.4% |
| Cancelled | 0.6% | 1.1% | 0.9% | 1.0% |
| Average departure delay (late minutes only) | 13.6 min | 16.2 min | 13.7 min | 17.5 min |
| Scheduled departures a day | 78 | 75 | 71 | 20,188 |
| Scheduled departures | 2,340 | 2,259 | 25,854 | 605,648 |
Airlines that month
| Reporting carrier | Flights | Share | On time | Avg arrival delay | Cancelled |
|---|---|---|---|---|---|
| WN Southwest Airlines | 1,047 | 45% | 82.0% | 5.1 min | 0.6% |
| AA American Airlines | 324 | 14% | 84.3% | 8.7 min | 1.5% |
| OO SkyWest Airlines | 217 | 9% | 93.1% | -8.5 min | 0.0% |
| UA United Airlines | 203 | 9% | 77.8% | 11.2 min | 0.0% |
| F9 Frontier Airlines | 200 | 9% | 72.0% | 17.5 min | 1.5% |
| DL Delta Air Lines | 163 | 7% | 91.4% | -6.2 min | 0.0% |
| AS Alaska Airlines | 115 | 5% | 70.4% | 13.0 min | 0.9% |
| B6 JetBlue Airways | 31 | 1% | 80.6% | 0.2 min | 0.0% |
| HA Hawaiian Airlines | 31 | 1% | 87.1% | -7.3 min | 0.0% |
| MQ Envoy Air | 9 | 0% | 88.9% | -5.4 min | 0.0% |
Busiest routes that month
| Route | Cities | Flights | On time | Avg arrival delay | Cancelled |
|---|---|---|---|---|---|
| ONT–PHX | Ontario to Phoenix | 294 | 88.4% | -0.3 min | 0.0% |
| ONT–DEN | Ontario to Denver | 261 | 66.7% | 21.6 min | 1.5% |
| ONT–SEA | Ontario to Seattle | 258 | 83.7% | 2.5 min | 0.8% |
| ONT–LAS | Ontario to Las Vegas | 223 | 76.2% | 14.4 min | 0.4% |
| ONT–DFW | Ontario to Dallas/Fort Worth | 214 | 78.5% | 13.4 min | 2.3% |
| ONT–SMF | Ontario to Sacramento | 184 | 84.8% | 3.2 min | 0.0% |
| ONT–OAK | Ontario to Oakland | 147 | 89.1% | -0.4 min | 1.4% |
| ONT–SFO | Ontario to San Francisco | 131 | 83.2% | -0.4 min | 0.0% |
| ONT–SJC | Ontario to San Jose | 123 | 85.4% | -0.4 min | 0.0% |
| ONT–SLC | Ontario to Salt Lake City | 113 | 92.9% | -5.4 min | 0.0% |
| ONT–ATL | Ontario to Atlanta | 81 | 91.4% | -7.4 min | 0.0% |
| ONT–IAH | Ontario to Houston | 44 | 88.6% | 0.0 min | 2.3% |
By scheduled departure hour
Delay causes
Questions and answers
How many flights left ONT on time in May 2025?
82.4% of 2,340 scheduled domestic departures left less than 15 minutes late, and 82.3% reached their destination on time. The national figures that month were 76.7% and 75.4%.
How does that compare with a year earlier?
In May 2024, 77.9% of 2,259 departures left on time and 1.1% were cancelled, against 82.4% and 0.6% in May 2025.
Provenance
Source: Bureau of Transportation Statistics, Reporting Carrier On-Time Performance, file for May 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.