Flight Check

Best Airline: DEN to ONT

Denver to Ontario — airline reliability comparison

United Airlines is the most reliable airline on the DEN to ONT route with a 78% on-time rate, compared to Southwest Airlines at 72%. Based on 2,955 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 Airlines78%
Frontier Airlines76%
Southwest Airlines72%

DEN to ONT Airline Comparison

AirlineOn-Time %Cancel %Avg DelayFlights
United AirlinesUABest78%0.4%66m2,955
Frontier AirlinesF976%1.0%64m2,276
Southwest AirlinesWNWorst72%0.7%50m4,717

Route Overview

74%
Overall On-Time
57m
Avg Delay
0.7%
Cancel Rate
9,955
Total Flights
DEN to ONT Route DetailsReturn: ONT to DEN
DEN AirportONT Airport

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