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

No clear winner: airlines and hours on this route all land within a few points of 82% on time.

Nonstops


Delta	BOI	SEA	1h 48m	87%	0.2%	2,365	Flying now
Alaska	BOI	SEA	1h 38m	78%	0.7%	2,942	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 Boise). Layovers up to 4 hours. Pick a connection for the details.


Alaska Details →	BOI 18:51 → LAX 20:10AS 2180 · flown by Horizon	1h 02m Los Angeles	LAX 21:12 → SEA 23:59AS 495	6h 08m	100%	92%
Delta Details →	BOI 07:00 → LAX 08:28DL 3725 · flown by SkyWest	1h 12m Los Angeles	LAX 09:40 → SEA 12:30DL 1714	6h 34m	99%	91%
Alaska Details →	BOI 05:57 → PDX 06:17AS 1566	1h 02m Portland	PDX 07:19 → SEA 08:20AS 2420 · flown by Horizon	3h 23m	94%	91%
Alaska Details →	BOI 07:37 → SJC 08:32AS 3131 · flown by SkyWest	1h 47m San Jose	SJC 10:19 → SEA 12:30AS 1311	5h 53m	99%	89%
Alaska Details →	BOI 07:40 → GEG 07:51AS 3198 · flown by SkyWest	3h 49m Spokane	GEG 11:40 → SEA 12:50AS 2262 · flown by Horizon	6h 10m	100%	88%
Delta Details →	BOI 18:42 → SLC 19:57DL 2920	2h 48m Salt Lake City	SLC 22:45 → SEA 23:59DL 2998	6h 17m	98%	88%
Alaska Details →	BOI 07:04 → SMF 07:34AS 2156 · flown by Horizon	2h 49m Sacramento	SMF 10:23 → SEA 12:22AS 1468	6h 18m	98%	88%
Southwest Details →	BOI 19:20 → SMF 19:45WN 717	2h 10m Sacramento	SMF 21:55 → SEA 23:50WN 4985	5h 30m	93%	87%
Tight connection: often missed
United Details →	BOI 14:00 → SFO 14:58UA 4661 · flown by SkyWest	1h 29m San Francisco	SFO 16:27 → SEA 18:47UA 2279	5h 47m	67%	51%
Delta Details →	BOI 18:42 → SLC 19:57DL 2920	47m Salt Lake City	SLC 20:44 → SEA 22:05DL 2016	4h 23m	68%	30%
United Details →	BOI 19:05 → SFO 19:58UA 649	56m San Francisco	SFO 20:54 → SEA 23:19UA 1007	5h 14m	24%	15%

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

LAX · 1h 12m · leaves 07:00 1%

DEN · 55m · leaves 07:20 2%

LAS · 55m · leaves 06:00 4%

Afternoon and evening

SLC · 47m · leaves 18:42 32%

SFO · 56m · leaves 19:05 76%

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 2259 BOI 14:47 → GEG Delta DL 3857 GEG 17:37 → SEA Connection details →	2h 42m	5h 18m	98%	91%
Alaska AS 3131 BOI 07:37 → SJC Delta DL 3736 SJC 11:29 → SEA Connection details →	2h 57m	7h 22m	99%	91%
Southwest WN 715 BOI 06:30 → SMF Alaska AS 1468 SMF 10:23 → SEA Connection details →	3h 28m	6h 52m	100%	90%

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