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

No clear winner: Southwest’s ONT → MDW flights land within a few points of 9 in 10 on time whatever the hour.

Nonstops (seasonal or thin)


Southwest	ONT	MDW	3h 45m	91%	0.3%	360	Flying now

Best connections, one ticket

Most reliable Quickest (80%+ on time)

Ranked by chance you reach Chicago on time. Total trip = scheduled departure to arrival, layover included (Chicago is 2 h ahead of Ontario). Layovers up to 4 hours. Pick a connection for the details.


Southwest Details →	ONT 18:30 → SMF 19:55WN 3170	3h 55m Sacramento	SMF 23:50 → MDW 05:45 +1WN 3802	9h 15m	98%	90%
Southwest Details →	ONT 19:55 → SJC 21:10WN 3164	1h 45m San Jose	SJC 22:55 → MDW 05:00 +1WN 3886	7h 05m	93%	87%
Delta Details →	ONT 22:00 → ATL 05:18DL 2892	3h 51m Atlanta	ATL 09:09 → MDW 10:09 +1DL 1063	10h 09m	100%	83%
Southwest Details →	ONT 05:50 → DEN 09:05WN 3144	55m Denver	DEN 10:00 → MDW 13:25WN 755	5h 35m	95%	83%
Southwest Details →	ONT 05:30 → LAS 06:35WN 3150	1h 45m Las Vegas	LAS 08:20 → MDW 13:55WN 2271	6h 25m	100%	75%
Southwest Details →	ONT 05:15 → PHX 06:30WN 864	1h 00m Phoenix	PHX 07:30 → MDW 12:50WN 3296	5h 35m	98%	74%
Southwest Details →	ONT 20:42 → PHX 21:58WN 3160	1h 57m Phoenix	PHX 23:55 → MDW 05:10 +1WN 3298	6h 28m	85%	71%
Delta Details →	ONT 11:50 → ATL 19:11DL 665	2h 04m Atlanta	ATL 21:15 → MDW 22:17DL 1076	8h 27m	95%	71%
Tight connection: often missed
Southwest Details →	ONT 21:40 → LAS 22:45WN 372	1h 10m Las Vegas	LAS 23:55 → MDW 05:25 +1WN 2276	5h 45m	74%	62%
Frontier Details →	ONT 08:17 → DFW 13:31F9 4690	59m Dallas-Fort Worth	DFW 14:30 → MDW 16:51F9 2882	6h 37m	75%	47%
Southwest Details →	ONT 16:20 → DAL 21:15WN 3247	1h 07m Dallas	DAL 22:22 → MDW 01:00 +1WN 1359	6h 17m	62%	20%

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

PHX · 1h 00m · leaves 05:15 2%

DEN · 55m · leaves 05:50 5%

Afternoon and evening

LAS · 1h 10m · leaves 21:40 26%

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.


Alaska AS 2456 ONT 17:32 → PDX Southwest WN 3203 PDX 23:30 → MDW Connection details →	3h 41m	9h 48m	99%	86%
United UA 2446 ONT 05:00 → DEN Southwest WN 755 DEN 10:00 → MDW Connection details →	1h 40m	6h 25m	92%	80%
American AA 864 ONT 19:13 → PHX Southwest WN 3298 PHX 23:55 → MDW Connection details →	3h 20m	7h 57m	94%	79%

Rank all connections, any airlines →

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