Flight Check

Best Airline: DEN to IAD

Denver to Washington — airline reliability comparison

United Airlines is the most reliable airline on the DEN to IAD route with a 81% on-time rate, compared to Southwest Airlines at 71%. Based on 8,820 flights tracked.

This route involves weather-prone airports and high-congestion airports, which can affect reliability regardless of airline.

Source: Bureau of Transportation Statistics. Updated October 2026.

On-Time Rate by Airline

United Airlines81%
Southwest Airlines71%

DEN to IAD Airline Comparison

AirlineOn-Time %Cancel %Avg DelayFlights
United AirlinesUABest81%1.3%74m8,820
Southwest AirlinesWNWorst71%0.4%48m2,693

Route Overview

79%
Overall On-Time
65m
Avg Delay
1%
Cancel Rate
11,518
Total Flights
DEN to IAD Route DetailsReturn: IAD to DEN
DEN AirportIAD Airport

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Data last updated October 2026. Source: Bureau of Transportation Statistics.