Flight Check

Best Airline: ATL to ONT

Atlanta to Ontario — airline reliability comparison

Delta Air Lines is the most reliable airline on the ATL to ONT route with a 77% on-time rate, compared to Frontier Airlines at 38%. Based on 3,321 flights tracked.

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

Source: Bureau of Transportation Statistics. Updated October 2026.

On-Time Rate by Airline

Delta Air Lines77%
Frontier Airlines38%

ATL to ONT Airline Comparison

AirlineOn-Time %Cancel %Avg DelayFlights
Delta Air LinesDLBest77%1.5%53m3,321
Frontier AirlinesF9Worst38%2.4%59m112

Route Overview

76%
Overall On-Time
55m
Avg Delay
1.5%
Cancel Rate
3,438
Total Flights
ATL to ONT Route DetailsReturn: ONT to ATL
ATL AirportONT Airport

Flying out of ATL? We'll brief you.

Delays, TSA, weather, gates — we'll let you know if something matters.

Free. No account needed.

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