United Airlines is the most reliable airline on the IAD to PHX route with a 84% on-time rate, compared to Southwest Airlines at 72%. Based on 2,652 flights tracked.
Source: Bureau of Transportation Statistics. Updated October 2026.Best Airline: IAD to PHX
Washington to Phoenix — airline reliability comparison
On-Time Rate by Airline
United Airlines84%
Southwest Airlines72%
IAD to PHX Airline Comparison
| Airline | On-Time % | Cancel % | Avg Delay | Flights |
|---|---|---|---|---|
| United AirlinesUABest | 84% | 1.4% | 71m | 2,652 |
| Southwest AirlinesWNWorst | 72% | 0.5% | 55m | 764 |
Route Overview
82%
Overall On-Time
66m
Avg Delay
1%
Cancel Rate
3,420
Total Flights
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Data last updated October 2026. Source: Bureau of Transportation Statistics.