Delta Air Lines is the most reliable airline on the IAD to SLC route with a 88% on-time rate, compared to United Airlines at 79%. Based on 1,308 flights tracked.
Source: Bureau of Transportation Statistics. Updated October 2026.Best Airline: IAD to SLC
Washington to Salt Lake City — airline reliability comparison
On-Time Rate by Airline
Delta Air Lines88%
United Airlines79%
IAD to SLC Airline Comparison
| Airline | On-Time % | Cancel % | Avg Delay | Flights |
|---|---|---|---|---|
| Delta Air LinesDLBest | 88% | 0.9% | 80m | 1,308 |
| United AirlinesUAWorst | 79% | 1.0% | 85m | 575 |
Route Overview
85%
Overall On-Time
85m
Avg Delay
1%
Cancel Rate
1,883
Total Flights
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Data last updated October 2026. Source: Bureau of Transportation Statistics.