Flight Check

Best Airline: STL to DEN

St. Louis to Denver — airline reliability comparison

SkyWest Airlines is the most reliable airline on the STL to DEN route with a 86% on-time rate, compared to Frontier Airlines at 73%. Based on 652 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

SkyWest Airlines86%
Southwest Airlines78%
United Airlines78%
Frontier Airlines73%

STL to DEN Airline Comparison

AirlineOn-Time %Cancel %Avg DelayFlights
SkyWest AirlinesOOBest86%0.8%90m652
Southwest AirlinesWN78%0.8%58m8,006
United AirlinesUA78%1.1%76m3,782
Frontier AirlinesF9Worst73%1.7%89m1,284

Route Overview

78%
Overall On-Time
67m
Avg Delay
1%
Cancel Rate
13,731
Total Flights
STL to DEN Route DetailsReturn: DEN to STL
STL AirportDEN Airport

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