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

No clear winner: Alaska’s IDA → SEA flights land within a few points of 85% on time whatever the hour.

Nonstops (seasonal or thin)


Alaska	IDA	SEA	2h 05m	85%	0.4%	721	Flying now

Best connections, one ticket

Most reliable Quickest (80%+ on time)

Ranked by chance you reach Seattle on time. Total trip = scheduled departure to arrival, layover included (Seattle is 1 h behind Idaho Falls). Layovers up to 4 hours. Pick a connection for the details.


Delta Details →	IDA 19:00 → SLC 20:09DL 3895 · flown by SkyWest	2h 36m Salt Lake City	SLC 22:45 → SEA 23:59DL 2998	5h 59m	98%	90%
United Details →	IDA 07:00 → DEN 08:55UA 4706 · flown by SkyWest	2h 27m Denver	DEN 11:22 → SEA 13:22UA 1424	7h 22m	97%	83%
United Details →	IDA 10:35 → DEN 12:28UA 5793 · flown by SkyWest	1h 32m Denver	DEN 14:00 → SEA 16:00UA 2164	6h 25m	93%	77%
Delta Details →	IDA 11:25 → SLC 12:31DL 3944 · flown by SkyWest	49m Salt Lake City	SLC 13:20 → SEA 14:40DL 2921	4h 15m	90%	76%
Delta Details →	IDA 15:22 → SLC 16:30DL 3765 · flown by SkyWest	50m Salt Lake City	SLC 17:20 → SEA 18:36DL 871	4h 14m	90%	73%
Delta Details →	IDA 06:00 → SLC 07:01DL 2335	49m Salt Lake City	SLC 07:50 → SEA 09:05DL 2874	4h 05m	77%	70%
United Details →	IDA 16:14 → DEN 18:05UA 5666 · flown by SkyWest	3h 05m Denver	DEN 21:10 → SEA 23:10UA 2651	7h 56m	95%	68%
United Details →	IDA 14:30 → DEN 16:18UA 2155	2h 52m Denver	DEN 19:10 → SEA 21:10UA 360	7h 40m	91%	62%
Tight connection: often missed
United Details →	IDA 16:14 → DEN 18:05UA 5666 · flown by SkyWest	1h 05m Denver	DEN 19:10 → SEA 21:10UA 360	5h 56m	72%	49%

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

SLC · 49m · leaves 06:00 23%

Afternoon and evening

SLC · 50m · leaves 15:22 10%

DEN · 1h 05m · leaves 16:14 28%

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 3421 IDA 16:14 → PDX Delta DL 3923 PDX 20:44 → SEA Connection details →	3h 54m	6h 42m	100%	79%
United UA 4706 IDA 07:00 → DEN Frontier F9 1175 DEN 12:00 → SEA Connection details →	3h 05m	8h 04m	96%	76%
Delta DL 3944 IDA 11:25 → SLC Alaska AS 734 SLC 16:00 → SEA Connection details →	3h 29m	6h 51m	99%	65%

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