Delta Air Lines is the most reliable airline on the SEA to SLC route with a 88% on-time rate, compared to Frontier Airlines at 78%. Based on 7,869 flights tracked.
Source: Bureau of Transportation Statistics. Updated October 2026.Best Airline: SEA to SLC
Seattle to Salt Lake City — airline reliability comparison
On-Time Rate by Airline
Delta Air Lines88%
SkyWest Airlines81%
Alaska Airlines80%
Frontier Airlines78%
SEA to SLC Airline Comparison
| Airline | On-Time % | Cancel % | Avg Delay | Flights |
|---|---|---|---|---|
| Delta Air LinesDLBest | 88% | 0.5% | 59m | 7,869 |
| SkyWest AirlinesOO | 81% | 0.1% | 46m | 1,629 |
| Alaska AirlinesAS | 80% | 1.3% | 46m | 4,436 |
| Frontier AirlinesF9Worst | 78% | 1.6% | 47m | 120 |
Route Overview
84%
Overall On-Time
52m
Avg Delay
0.7%
Cancel Rate
14,131
Total Flights
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Data last updated October 2026. Source: Bureau of Transportation Statistics.