Seattle (SEA) to Ontario (ONT) flights
Alaska Airlines, SkyWest Airlines, Frontier Airlines fly nonstop from Seattle-Tacoma International Airport to Ontario International Airport, with about 58 flights a week in July 2026. The 956-mile flight takes about 2h 39m gate to gate.
- Distance
- 956 mi · 1,539 km
- Flight time
- 2h 39m
- Airlines
- 3
- Seats filled
- 82%
Airlines flying SEA to ONT
| Airline | Flights a week | Aircraft | Passengers (12 months) | Flight time |
|---|---|---|---|---|
| Alaska Airlines | 31 | Boeing 737-900ER, Boeing 737 MAX 9, Boeing 737-800 | 177,678 | 2h 36m |
| SkyWest Airlines | 20 | Embraer E175 | 64,713 | 2h 43m |
| Frontier Airlines | 7 | Airbus A321, Airbus A320neo, Airbus A320-100/200 | 26,171 | 2h 40m |
| Delta Air LinesSeasonal or ended | n/a | Airbus A220-100, Boeing 737-800, Airbus A220-300 | 3,416 | 2h 45m |
Airlines are the operating carrier: regional airlines such as SkyWest or Horizon often fly under a larger airline's brand.
SEA to ONT flight schedule
9 flight numbers flew this route in August 2026, 8 of them almost daily. The first usually leaves at 8:22am and the last at 8:33pm. Times are local and can change; check with the airline before you book.
| Flight | Departs | Arrives | Days flown in August 2026 | On time (12 months) |
|---|---|---|---|---|
| DL 4070Delta Air Lines · operated by SkyWest Airlines | 8:22am | 11:16am | 26 | 87% |
| AS 1364Alaska Airlines | 8:33am | 11:14am | 31 | 90% |
| AS 565Alaska Airlines | 10:25am | 1:09pm | 18 | 74% |
| F9 2276Frontier Airlines | 11:54am | 2:45pm | 31 | 88% |
| AS 571Alaska Airlines | 1:50pm | 4:30pm | 28 | 50% |
| DL 4031Delta Air Lines · operated by SkyWest Airlines | 2:30pm | 5:21pm | 31 | 87% |
| AS 592Alaska Airlines | 4:22pm | 8:30pm | 26 | 72% |
| DL 3884Delta Air Lines · operated by SkyWest Airlines | 7:50pm | 10:45pm | 31 | 87% |
| AS 489Alaska Airlines | 8:33pm | 11:11pm | 27 | 70% |
Is SEA to ONT on time?
From September 2025 to August 2026, 83% of 2,487 flights arrived within 15 minutes of schedule and 1% were cancelled. Flights leaving around 8am were the most punctual (91%), those around 9pm the least (71%). Most delay time was caused by the airline (crew, maintenance, cleaning, fuelling) (55%).
| Airline | Flights | On time | Average delay | Cancelled |
|---|---|---|---|---|
| Alaska Airlines | 1,257 | 78% | 12 min | 1.5% |
| Delta Air Lines | 1,061 | 88% | 7 min | 0.4% |
| Frontier Airlines | 169 | 84% | 13 min | 1.8% |
Airlines as sold: flights operated by regional partners count under the airline on the ticket. Average delay is across all completed flights, early arrivals counted as zero.
On-time arrivals by departure time
| Scheduled departure | Flights | On time, relative | On time |
|---|---|---|---|
| 7am to 8am | 119 | 91% | |
| 8am to 9am | 495 | 91% | |
| 9am to 10am | 57 | 88% | |
| 10am to 11am | 92 | 81% | |
| 11am to 12pm | 231 | 83% | |
| 12pm to 1pm | 160 | 85% | |
| 1pm to 2pm | 82 | 53% | |
| 2pm to 3pm | 314 | 85% | |
| 3pm to 4pm | 120 | 78% | |
| 4pm to 5pm | 53 | 77% | |
| 5pm to 6pm | 50 | 48% | |
| 7pm to 8pm | 288 | 86% | |
| 8pm to 9pm | 218 | 79% | |
| 9pm to 10pm | 162 | 71% |
Flights by month
| Month | Flights | Flights, relative | Passengers |
|---|---|---|---|
| August 2025 | 266 | 33,530 | |
| September 2025 | 217 | 24,889 | |
| October 2025 | 200 | 21,344 | |
| November 2025 | 209 | 23,052 | |
| December 2025 | 201 | 23,505 | |
| January 2026 | 161 | 17,333 | |
| February 2026 | 136 | 15,246 | |
| March 2026 | 174 | 17,814 | |
| April 2026 | 201 | 18,382 | |
| May 2026 | 249 | 22,691 | |
| June 2026 | 236 | 25,618 | |
| July 2026 | 255 | 28,733 |
Related
Source: US Department of Transportation, T-100 Segment data, August 2025 to July 2026.