SkyWest Airlines is the most reliable airline on the SEA to ONT route with a 90% on-time rate, compared to Frontier Airlines at 77%. Based on 2,881 flights tracked.
Source: Bureau of Transportation Statistics. Updated October 2026.Best Airline: SEA to ONT
Seattle to Ontario — airline reliability comparison
On-Time Rate by Airline
SkyWest Airlines90%
Delta Air Lines84%
Alaska Airlines78%
Frontier Airlines77%
SEA to ONT Airline Comparison
| Airline | On-Time % | Cancel % | Avg Delay | Flights |
|---|---|---|---|---|
| SkyWest AirlinesOOBest | 90% | 0.1% | 48m | 2,881 |
| Delta Air LinesDL | 84% | 0.8% | 73m | 1,023 |
| Alaska AirlinesAS | 78% | 1.6% | 45m | 4,440 |
| Frontier AirlinesF9Worst | 77% | 2.0% | 74m | 470 |
Route Overview
82%
Overall On-Time
51m
Avg Delay
1%
Cancel Rate
8,862
Total Flights
Flying out of SEA? We'll brief you.
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Data last updated October 2026. Source: Bureau of Transportation Statistics.