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Ranking & search details
3 nonstop, 37 with 1 connection, 6 with 2 · ranked by overall best · 9 hidden by your Most reliable time setting (they leave at other times of day) · showing the top 3
Most reliable time: morning departures (5–11 AM), the window with the best on-time odds for this trip. Turn off “Most reliable” under Departure time in Advanced settings to see every time.
37 matching trips
Why this is our top pick
- This morning flight leaves in the most reliable time of day on this route: its best departures have a 78% reliability rating vs 63% for night departures.
- Delta trips we compared arrive on time 79% of the time on average, 4 points more often than Southwest, American and United (75%).
10:00 AM4:17 PMATL → ONT
Delta · DL 663 / OO 3762
9h 04m1 stop
3h 00m in SLC
One ticket
93%arrive on time98% connections madeCheck fares
6:00 AM10:55 AMATL → ONT
Southwest · WN 1763 / WN 2209
7h 55m1 stop
2h 25m in PHX
One ticket
78%arrive on time96% connections madeCheck fares
Aircraft and legroom reflect the planes each flight has flown recently. Airlines can swap planes and seat maps change, so check the airline’s seat map when you book.
ATL → ONT
Atlanta to Ontario: 941 nonstop flights a year
On time (12 months)
76%
Cancelled
1.7%
avg delay 14 min
Best time to leave
Before 9 AM
89% on time vs 51% after 9 PM
Most reliable airline
Delta
74% chance on time
Fares open on our travel partner (Aviasales). Pick the flight number you chose here.
Airlines on this route
Season-adjusted chance of operating and arriving on time.
- Delta Air Lines74%
941 flights · 76% on time as flown · 1.7% cancel
On time by departure time
All airlines, scheduled local departure, Jun 2025 to May 2026.
- Before 9 AM89%
57 flights · avg delay 4 min
- 9 AM to noon85%
308 flights · avg delay 9 min
- 3 to 6 PM71%
212 flights · avg delay 13 min
- 6 to 9 PM73%
287 flights · avg delay 17 min
- After 9 PM51%
77 flights · avg delay 37 min
Best day: Wednesday (78%). Worst: Sunday (72%).
Smarter routing
Nearby airports that run more on time
ATL → LAX 77% chance on time
Hartsfield Jackson Atlanta International Airport to Los Angeles International Airport · 5,097 flights a year · 47 mi from your airports · yours: 74%
Historical odds, not a guarantee. Built from the US DOT Bureau of Transportation Statistics on-time reports (Jun 2025 to May 2026), FAA ground stop and delay program advisories, and 20 years of airport weather observations. Covers US airlines that report to the DOT; schedules are flights operated recently, so confirm times when you book. ATIS Alerts is not affiliated with any airline. Fares are what Aviasales travelers saw in recent searches (USD, one way, 1 adult), not live quotes; the partner site shows the current price. Fare links go to our travel partner and may earn us a commission at no cost to you. Affiliate disclosure