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

No clear winner: United’s ONT → ORD flights land within a few points of 4 in 5 on time whatever the hour.

Nonstops (seasonal or thin)


United	ONT	ORD	4h 03m	81%	1.4%	291	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.


Delta Details →	ONT 22:00 → ATL 05:18DL 2892	2h 07m Atlanta	ATL 07:25 → ORD 08:35 +1DL 1178	8h 35m	100%	84%
United Details →	ONT 18:39 → SFO 20:07UA 5624 · flown by SkyWest	3h 23m San Francisco	SFO 23:30 → ORD 05:57 +1UA 368	9h 18m	100%	83%
Alaska Details →	ONT 17:32 → PDX 19:49AS 2456 · flown by Horizon	3h 10m Portland	PDX 22:59 → ORD 05:00 +1AS 376	9h 28m	100%	83%
American Details →	ONT 22:10 → CLT 05:48AA 2237	1h 58m Charlotte	CLT 07:46 → ORD 09:02 +1AA 2843	8h 52m	97%	82%
United Details →	ONT 05:00 → DEN 08:20UA 2446	2h 55m Denver	DEN 11:15 → ORD 14:55UA 2865	7h 55m	99%	81%
American Details →	ONT 23:59 → DFW 05:00AA 3006	3h 30m Dallas-Fort Worth	DFW 08:30 → ORD 11:10 +1AA 1059	9h 11m	100%	81%
Alaska Details →	ONT 12:04 → SEA 14:44AS 654	3h 04m Seattle	SEA 17:48 → ORD 23:59AS 538	9h 55m	100%	77%
American Details →	ONT 06:11 → PHX 07:30AA 1194	1h 00m Phoenix	PHX 08:30 → ORD 14:21AA 319	6h 10m	92%	76%
Tight connection: often missed
United Details →	ONT 13:50 → SFO 15:15UA 1375	1h 06m San Francisco	SFO 16:21 → ORD 22:59UA 1482	7h 09m	62%	50%
American Details →	ONT 14:15 → DFW 19:30AA 2239	1h 30m Dallas-Fort Worth	DFW 21:00 → ORD 23:39AA 2346	7h 24m	71%	40%
American Details →	ONT 12:35 → DFW 17:50AA 2242	48m Dallas-Fort Worth	DFW 18:38 → ORD 21:22AA 1424	6h 47m	70%	26%

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 15m · leaves 05:00 3%

SEA · 1h 18m · leaves 06:20 6%

PHX · 1h 00m · leaves 06:11 8%

Afternoon and evening

SEA · 1h 03m · leaves 14:05 20%

DFW · 48m · leaves 12:35 30%

SFO · 1h 06m · leaves 13:50 38%

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.


Southwest WN 3150 ONT 05:30 → LAS American AA 2020 LAS 09:40 → ORD Connection details →	3h 05m	8h 12m	100%	90%
Delta DL 4031 ONT 17:59 → SEA American AA 2881 SEA 23:56 → ORD Connection details →	3h 06m	10h 03m	98%	90%
Alaska AS 2456 ONT 17:32 → PDX United UA 2094 PDX 22:40 → ORD Connection details →	2h 51m	9h 13m	98%	87%

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