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 SJC → ONT flights land within a few points of 83% on time whatever the hour.

Nonstops


Southwest	SJC	ONT	1h 15m	83%	0.2%	1,317	Flying now

Best connections, one ticket

Most reliable Quickest (80%+ on time)

Ranked by chance you reach Ontario on time. Total trip = scheduled departure to arrival, layover included. Layovers up to 4 hours. Pick a connection for the details.


Southwest Details →	SJC 06:25 → PHX 08:20WN 3186	1h 45m Phoenix	PHX 10:05 → ONT 11:20WN 431	4h 55m	100%	88%
Alaska Details →	SJC 09:46 → PDX 11:31AS 2256 · flown by Horizon	2h 59m Portland	PDX 14:30 → ONT 16:52AS 2093 · flown by Horizon	7h 06m	98%	88%
Delta Details →	SJC 06:00 → SLC 08:55DL 1314	2h 24m Salt Lake City	SLC 11:19 → ONT 12:10DL 3172	6h 10m	98%	88%
Delta Details →	SJC 17:01 → SLC 19:57DL 1260	3h 02m Salt Lake City	SLC 22:59 → ONT 23:48DL 1614	6h 47m	99%	87%
Delta Details →	SJC 09:45 → SLC 12:48DL 4026 · flown by SkyWest	2h 57m Salt Lake City	SLC 15:45 → ONT 16:41DL 4443 · flown by SkyWest	6h 56m	98%	86%
Southwest Details →	SJC 07:40 → LAS 09:10WN 1277	2h 20m Las Vegas	LAS 11:30 → ONT 12:32WN 2298	4h 52m	100%	82%
Southwest Details →	SJC 06:00 → LAS 07:35WN 2280	1h 30m Las Vegas	LAS 09:05 → ONT 10:10WN 4179	4h 10m	100%	80%
Frontier Details →	SJC 14:12 → LAS 15:50F9 1590	2h 53m Las Vegas	LAS 18:43 → ONT 19:51F9 2231	5h 39m	98%	76%
Tight connection: often missed
Alaska Details →	SJC 17:28 → SEA 19:39AS 1413	54m Seattle	SEA 20:33 → ONT 23:11AS 489	5h 43m	74%	52%

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

LAS · 50m · leaves 09:10 5%

Afternoon and evening

SLC · 52m · leaves 19:10 19%

PDX · 1h 01m · leaves 18:37 24%

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 1311 SJC 10:19 → SEA Delta DL 4031 SEA 14:35 → ONT Connection details →	2h 05m	7h 00m	98%	84%
Southwest WN 3232 SJC 11:40 → PHX American AA 864 PHX 17:07 → ONT Connection details →	3h 32m	6h 41m	100%	83%
Southwest WN 2369 SJC 09:10 → LAS Frontier F9 1357 LAS 13:59 → ONT Connection details →	3h 19m	5h 59m	100%	82%

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