Flight Check

Best Airline: IAD to DEN

Washington to Denver — airline reliability comparison

United Airlines is the most reliable airline on the IAD to DEN route with a 82% on-time rate, compared to Southwest Airlines at 81%. Based on 8,852 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 Airlines82%
Southwest Airlines81%

IAD to DEN Airline Comparison

AirlineOn-Time %Cancel %Avg DelayFlights
United AirlinesUABest82%1.0%74m8,852
Southwest AirlinesWNWorst81%0.6%56m2,692

Route Overview

82%
Overall On-Time
69m
Avg Delay
0.9%
Cancel Rate
11,550
Total Flights
IAD to DEN Route DetailsReturn: DEN to IAD
IAD AirportDEN Airport

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