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 5% of the time at 8 am and 22% of the time at 7 pm.

Best connections, any airlines

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


United Details →	IAD 06:30 → DEN 08:22UA 2031	3h 03m Denver	DEN 11:25 → ONT 12:47UA 430	9h 17m	100%	88%
United + Deltatwo ticketsDetails →	IAD 09:00 → SEA 11:51UA 2101	2h 44m Seattle	SEA 14:35 → ONT 17:19DL 4031 · flown by SkyWest	11h 19m	99%	87%
Delta Details →	IAD 07:15 → SLC 09:52DL 432	1h 27m Salt Lake City	SLC 11:19 → ONT 12:10DL 3172	7h 55m	93%	83%
United + Deltatwo ticketsDetails →	IAD 13:10 → SEA 15:55UA 2241	3h 55m Seattle	SEA 19:50 → ONT 22:41DL 3884 · flown by SkyWest	12h 31m	97%	81%
United Details →	IAD 14:51 → SFO 17:38UA 2862	3h 22m San Francisco	SFO 21:00 → ONT 22:37UA 552	10h 46m	98%	81%
Alaska + Frontiertwo ticketsDetails →	IAD 06:03 → SEA 08:48AS 409	3h 05m Seattle	SEA 11:53 → ONT 14:39F9 2276	11h 36m	98%	81%
Frontier Details →	IAD 09:50 → LAS 11:45F9 4277	2h 14m Las Vegas	LAS 13:59 → ONT 15:09F9 1357	8h 19m	95%	78%
United + Deltatwo ticketsDetails →	IAD 17:50 → SLC 20:46UA 2410	2h 13m Salt Lake City	SLC 22:59 → ONT 23:48DL 1614	8h 58m	89%	77%
Tight connection: often missed
United Details →	IAD 12:40 → SFO 15:27UA 1434	50m San Francisco	SFO 16:17 → ONT 17:54UA 5613 · flown by SkyWest	8h 14m	68%	43%
American Details →	IAD 19:31 → DFW 21:50AA 1904	1h 05m Dallas-Fort Worth	DFW 22:55 → ONT 23:59 +1AA 1534	7h 31m	54%	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.

Afternoon and evening

DEN · 1h 17m · leaves 15:56 11%

SFO · 50m · leaves 12:40 32%

DFW · 1h 05m · leaves 19:31 46%

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