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 90-minute layover misses 1 time in 10 at 9 am and 23% of the time at 8 pm.

Nonstops


Frontier	DEN	ONT	2h 21m	81%	0.2%	551	Flying now
United	DEN	ONT	2h 22m	81%	0.0%	823	Flying now
Southwest	DEN	ONT	2h 20m	71%	0.1%	1,268	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 (Ontario is 1 h behind Denver). Layovers up to 4 hours. Pick a connection for the details.


Southwest Details →	DEN 07:45 → OAK 09:25WN 1240	1h 25m Oakland	OAK 10:50 → ONT 12:10WN 3062	5h 25m	100%	95%
Delta Details →	DEN 07:05 → SLC 08:36DL 1581	2h 43m Salt Lake City	SLC 11:19 → ONT 12:10DL 3172	6h 05m	96%	87%
Delta Details →	DEN 19:00 → SLC 20:38DL 2663	2h 21m Salt Lake City	SLC 22:59 → ONT 23:48DL 1614	5h 48m	96%	84%
Southwest Details →	DEN 06:15 → PHX 07:05WN 1675	3h 00m Phoenix	PHX 10:05 → ONT 11:20WN 431	6h 05m	100%	84%
Southwest Details →	DEN 07:40 → LAS 08:35WN 1559	2h 55m Las Vegas	LAS 11:30 → ONT 12:32WN 2298	5h 52m	100%	82%
Southwest Details →	DEN 07:50 → SJC 09:25WN 494	1h 25m San Jose	SJC 10:50 → ONT 12:05WN 3151	5h 15m	95%	82%
Southwest Details →	DEN 05:45 → LAS 06:40WN 3106	2h 25m Las Vegas	LAS 09:05 → ONT 10:10WN 4179	5h 25m	100%	82%
Southwest Details →	DEN 10:20 → SMF 11:55WN 1740	2h 05m Sacramento	SMF 14:00 → ONT 15:20WN 3807	6h 00m	100%	81%
Tight connection: often missed
American Details →	DEN 18:10 → DFW 21:18AA 1322	1h 37m Dallas-Fort Worth	DFW 22:55 → ONT 23:59 +1AA 1534	6h 52m	71%	25%
Southwest Details →	DEN 18:55 → PHX 19:50WN 1683	1h 10m Phoenix	PHX 21:00 → ONT 22:10WN 2862	4h 15m	38%	14%
Southwest Details →	DEN 20:05 → PHX 21:00WN 4447	50m Phoenix	PHX 21:50 → ONT 23:00WN 3313	3h 55m	30%	12%

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

DFW · 1h 13m · leaves 06:20 6%

PHX · 1h 00m · leaves 08:00 17%

SLC · 47m · leaves 05:40 19%

Afternoon and evening

SFO · 1h 20m · leaves 17:54 23%

LAS · 55m · leaves 20:35 62%

PHX · 50m · leaves 20:05 70%

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.


Frontier F9 3219 DEN 06:00 → SLC Delta DL 3172 SLC 11:19 → ONT Connection details →	3h 48m	7h 10m	99%	89%
Southwest WN 4027 DEN 10:05 → SLC Delta DL 4443 SLC 15:45 → ONT Connection details →	4h 00m	7h 36m	100%	87%
United UA 5762 DEN 17:45 → SLC Delta DL 1614 SLC 22:59 → ONT Connection details →	3h 34m	7h 03m	96%	84%

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