Airport reliability
Ontario (ONT) on-time performance
How reliably flights leave Ontario, CA (ONT) and reach their destinations, by airline, departure hour and month, September 2025 to August 2026.
Ontario, CA25,791 departures in 12 months
- Departures on time
- 81.1% U.S. average 75.6%
- Cancelled
- 0.9% U.S. average 1.9%
- 60+ minutes late
- 5.5% U.S. average 8.1%
- Scheduled departures
- 25,791 12 months
What this means
ONT departures beat the U.S. average.
- 81.1% of the 25,791 scheduled departures from Ontario (ONT) arrived at their destination on time, 5.5 points higher than the U.S. average of 75.6%.
- 0.9% of departures were cancelled (U.S. average 1.9%), and 5.5% arrived an hour or more late.
- Flights arriving at ONT were on time 76.9% of the time.
- Among airlines with at least 300 departures, Delta Air Lines was the most punctual from ONT (88.1%) and Frontier Airlines the least (74.2%).
- Over the last 3 years, February was the most reliable month for departures from ONT (86.8% on time) and July the least reliable (78.0%).
- Cancellations peaked in January, when 2.0% of flights were cancelled.
- Flights scheduled to depart before 6 am were the most punctual (94.8% on time); flights scheduled to depart 8 pm to 9 pm were the least (67.7%).
Airlines at ONT
Ranked by on-time arrival
| Airline | On time | Cancelled | 60+ min late | Avg delay when late | Departures |
|---|---|---|---|---|---|
| Delta Air Lines | 88.1% | 1.5% | 4.5% | 93 min | 1,811 |
| SkyWest AirlinesSold as United Express, Delta Connection, American Eagle, Alaska | 86.9% | 0.4% | 4.2% | 78 min | 1,771 |
| Alaska Airlines | 83.4% | 1.3% | 3.9% | 54 min | 2,098 |
| American Airlines | 81.3% | 1.8% | 6.3% | 103 min | 3,545 |
| Southwest Airlines | 80.7% | 0.4% | 4.7% | 51 min | 11,643 |
| United Airlines | 78.7% | 0.5% | 6.9% | 71 min | 2,429 |
| Frontier Airlines | 74.2% | 1.3% | 9.3% | 75 min | 2,284 |
| JetBlue Airways | 60.6% | 4.2% | 18.2% | 191 min | 165 |
| Envoy AirSold as American Eagle | Insufficient sample | 45 | |||
Tap a heading to sort.
On-time rate by departure hour
Share of scheduled flights on time ONT average 81.1%
Show as table
| Period | On time | Flights |
|---|---|---|
| Departing before 6 am | 94.8% | 1,588 |
| Departing 6 am to 7 am | 92.0% | 3,770 |
| Departing 7 am to 8 am | 89.3% | 1,582 |
| Departing 8 am to 9 am | 85.5% | 1,443 |
| Departing 9 am to 10 am | 84.7% | 1,274 |
| Departing 10 am to 11 am | 82.7% | 1,607 |
| Departing 11 am to noon | 81.0% | 1,345 |
| Departing noon to 1 pm | 77.7% | 1,739 |
| Departing 1 pm to 2 pm | 74.5% | 1,967 |
| Departing 2 pm to 3 pm | 67.9% | 1,064 |
| Departing 3 pm to 4 pm | 74.5% | 1,148 |
| Departing 4 pm to 5 pm | 73.6% | 1,385 |
| Departing 5 pm to 6 pm | 79.3% | 1,262 |
| Departing 6 pm to 7 pm | 68.6% | 1,215 |
| Departing 7 pm to 8 pm | 72.4% | 847 |
| Departing 8 pm to 9 pm | 67.7% | 662 |
| Departing 9 pm to 10 pm | 71.0% | 517 |
| Departing 10 pm to 11 pm | 83.2% | 785 |
| Departing 11 pm to midnight | 78.5% | 591 |
Best and worst months at ONT
Share of scheduled flights on time 12-month average 81.1%
Show as table
| Period | On time | Flights |
|---|---|---|
| January | 84.0% | 5,721 |
| February | 86.8% | 5,239 |
| March | 82.7% | 6,210 |
| April | 83.5% | 6,467 |
| May | 79.8% | 6,897 |
| June | 78.2% | 6,915 |
| July | 78.0% | 7,181 |
| August | 82.1% | 6,947 |
| September | 85.3% | 6,571 |
| October | 85.1% | 6,868 |
| November | 84.9% | 6,490 |
| December | 84.9% | 6,332 |
Month by month, last 12 months
Share of scheduled flights on time U.S. average 75.6%
Show as table
| Period | On time | Flights |
|---|---|---|
| Sep 2025 | 84.2% | 2,177 |
| Oct 2025 | 81.1% | 2,265 |
| Nov 2025 | 80.1% | 2,184 |
| Dec 2025 | 81.7% | 2,132 |
| Jan 2026 | 85.0% | 1,892 |
| Feb 2026 | 87.4% | 1,734 |
| Mar 2026 | 81.7% | 2,081 |
| Apr 2026 | 82.4% | 2,119 |
| May 2026 | 79.3% | 2,298 |
| Jun 2026 | 75.7% | 2,304 |
| Jul 2026 | 77.0% | 2,377 |
| Aug 2026 | 80.0% | 2,228 |
Busiest routes from ONT
| To | On time | Cancelled | Airlines | Flights |
|---|---|---|---|---|
| Phoenix (PHX) | 81.8% | 0.6% | 4 | 3,011 |
| Denver (DEN) | 81.2% | 0.4% | 3 | 2,624 |
| Seattle (SEA) | 84.9% | 1.1% | 4 | 2,488 |
| Las Vegas (LAS) | 75.5% | 0.9% | 2 | 2,469 |
| Dallas/Fort Worth (DFW) | 78.3% | 2.4% | 2 | 2,274 |
| Sacramento (SMF) | 84.9% | 0.3% | 1 | 2,119 |
| Oakland (OAK) | 85.5% | 0.6% | 1 | 1,450 |
| San Francisco (SFO) | 60.2% | 0.7% | 3 | 1,335 |
| San Jose (SJC) | 85.8% | 0.1% | 1 | 1,320 |
| Salt Lake City (SLC) | 90.2% | 0.9% | 3 | 1,239 |
| Atlanta (ATL) | 86.4% | 1.8% | 1 | 934 |
| Houston (IAH) | 85.4% | 1.2% | 2 | 574 |
| Portland (PDX) | 90.8% | 0.7% | 3 | 565 |
| Honolulu (HNL) | 84.5% | 0.2% | 2 | 446 |
| Dallas (DAL) | 75.4% | 1.5% | 1 | 395 |
| Houston (HOU) | 63.1% | 0.0% | 1 | 363 |
| Chicago (MDW) | 90.3% | 0.3% | 1 | 360 |
| Austin (AUS) | 73.1% | 0.3% | 2 | 338 |
| Nashville (BNA) | 75.3% | 0.6% | 1 | 336 |
| Charlotte (CLT) | 86.0% | 1.0% | 1 | 300 |
Sources & data dates
- Source
- U.S. DOT Bureau of Transportation Statistics, Reporting Carrier On-Time Performance (1987-present)
- Period
- September 2025 to August 2026 (12 months); month-of-year patterns September 2023 to August 2026
- Data through
- August 2026
- Processed
- 2026-11-03
- Scope
- Scheduled nonstop domestic departures from Ontario, CA (ONT) by airlines that report to the DOT.
- Method
- Rates use all scheduled flights as the denominator; cancelled and diverted flights count as not on time. Figures based on fewer than 50 scheduled flights are suppressed. Full methodology.