Itineraries flown on 20+ days in the Jun 6 – Jul 31, 2026 schedule · each leg’s record Aug 2025 – Jul 2026

Connect in the morning. The same one-hour layover misses 4% of the time at 9 am and 14% of the time at 9 pm.

Nonstops (seasonal or thin)


Delta	ONT	ATL	4h 18m	90%	1.8%	937	Flying now

Best connections, any airlines

Most reliable Quickest (80%+ on time)

Ranked by chance you reach Atlanta on time. Total trip = scheduled departure to arrival, layover included (Atlanta is 3 h ahead of Ontario). Layovers up to 4 hours. Pick a connection for the details.


Southwest Details →	ONT 21:40 → BWI 05:30WN 3143	2h 50m Baltimore	BWI 08:20 → ATL 10:20 +1WN 3931	9h 38m	100%	92%
Southwest Details →	ONT 23:55 → MDW 05:40WN 3153	1h 35m Chicago	MDW 07:15 → ATL 10:05 +1WN 3054	7h 10m	98%	91%
Delta Details →	ONT 17:59 → SEA 20:50DL 4031 · flown by SkyWest	3h 09m Seattle	SEA 23:59 → ATL 07:46 +1DL 652	10h 47m	98%	87%
Alaska + Deltatwo ticketsDetails →	ONT 07:00 → PDX 09:15AS 345	2h 25m Portland	PDX 11:40 → ATL 19:26DL 539	9h 26m	100%	85%
Alaska Details →	ONT 17:26 → SEA 20:06AS 575	3h 25m Seattle	SEA 23:31 → ATL 07:24 +1AS 464	10h 58m	100%	85%
Southwest + Deltatwo ticketsDetails →	ONT 05:30 → LAS 06:35WN 3150	1h 40m Las Vegas	LAS 08:15 → ATL 15:17DL 927	6h 47m	95%	85%
Delta Details →	ONT 17:21 → SLC 20:17DL 4443 · flown by SkyWest	3h 18m Salt Lake City	SLC 23:35 → ATL 05:15 +1DL 912	8h 54m	96%	84%
American Details →	ONT 22:10 → CLT 05:48AA 2237	3h 22m Charlotte	CLT 09:10 → ATL 10:41 +1AA 5039 · flown by PSA	9h 31m	99%	84%
Tight connection: often missed
American Details →	ONT 14:15 → DFW 19:30AA 2239	1h 40m Dallas-Fort Worth	DFW 21:10 → ATL 00:19 +1AA 2749	7h 04m	71%	35%
United Details →	ONT 18:39 → SFO 20:07UA 5624 · flown by SkyWest	1h 13m San Francisco	SFO 21:20 → ATL 05:20 +1UA 1603	7h 41m	29%	24%
Southwest Details →	ONT 14:30 → DEN 17:40WN 3147	1h 25m Denver	DEN 19:05 → ATL 00:55 +1WN 1472	6h 35m	65%	8%

Same layover, different day-part

How often the first flight arrives too late to connect (45 min minimum), for one-ticket layovers of 45–80 minutes.

Morning

DEN · 1h 10m · leaves 05:50 2%

SFO · 1h 20m · leaves 06:00 4%

SLC · 1h 05m · leaves 06:00 4%

Afternoon and evening

DEN · 1h 10m · leaves 13:18 13%

SEA · 55m · leaves 17:59 14%

SFO · 1h 13m · leaves 18:39 71%

Delays build through the day, so an afternoon first leg eats the layover. A short connection is fine early in the morning and a gamble later on.

Mixing airlines

One ticketMiss it and the airline rebooks you; bags go through. 45 min is enough.

Separate ticketsMiss it and you buy a new ticket. Re-check bags, clear security again: we require 90 min.

The table above includes two-ticket connections (marked “two tickets”), held to the 90-minute minimum. One ticket only →

Regional partners count as the airline that sells them: SkyWest flying Delta Connection is one Delta ticket.

How these are worked out. Makes the connection: share of the last year’s flights where the first flight arrived with at least 45 minutes to spare (90 on separate tickets). Arrives on time: first flight not cancelled × connection made × second flight not cancelled and arriving within 15 minutes. Not yet counted: the second flight also leaving late (which helps), gate-to-gate distance at the hub, and rebooking after a missed connection.

About this data: US DOT on-time records, Aug 2025 – Jul 2026, all US airlines; regional flights count under the airline that sells them. Schedules (which flights and connections exist, and their times) are as of Jun 6 – Jul 31, 2026; seasonal flights outside that window aren’t ranked. Rebuilt monthly. JSON