SkyWest Airlines is the most reliable airline on the ONT to SEA route with a 92% on-time rate, compared to Frontier Airlines at 83%. Based on 2,881 flights tracked.
Source: Bureau of Transportation Statistics. Updated October 2026.Best Airline: ONT to SEA
Ontario to Seattle — airline reliability comparison
On-Time Rate by Airline
SkyWest Airlines92%
Delta Air Lines90%
Alaska Airlines84%
Frontier Airlines83%
ONT to SEA Airline Comparison
| Airline | On-Time % | Cancel % | Avg Delay | Flights |
|---|---|---|---|---|
| SkyWest AirlinesOOBest | 92% | 0.2% | 74m | 2,881 |
| Delta Air LinesDL | 90% | 0.8% | 88m | 1,022 |
| Alaska AirlinesAS | 84% | 1.7% | 58m | 4,438 |
| Frontier AirlinesF9Worst | 83% | 0.9% | 96m | 469 |
Route Overview
87%
Overall On-Time
68m
Avg Delay
1%
Cancel Rate
8,858
Total Flights
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Data last updated October 2026. Source: Bureau of Transportation Statistics.