Sun, Oct 4 has passed, so this is the 12-month record.

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 75-minute layover misses 6% of the time at 12 pm and 1 time in 5 at 5 pm.

Nonstops (seasonal or thin)


United	DEN	BUF	3h 17m	73%	0.0%	294	Flying now
Southwest	DEN	BUF	3h 05m	62%	0.4%	258	Flying now
Frontier	DEN	BUF	3h 14m	83%few flights	0.0%	35	Not flying now

Best connections, one ticket

Most reliable Quickest (80%+ on time)

Ranked by chance you reach Buffalo on time. Total trip = scheduled departure to arrival, layover included (Buffalo is 2 h ahead of Denver). Layovers up to 4 hours. Pick a connection for the details.


United Details →	DEN 23:59 → IAD 05:27UA 1924	2h 58m Dulles	IAD 08:25 → BUF 09:51 +1UA 3514 · flown by Republic	7h 52m	100%	90%
Delta Details →	DEN 00:59 → DTW 05:48DL 1096	1h 19m Detroit	DTW 07:07 → BUF 08:23DL 3639 · flown by SkyWest	5h 24m	94%	87%
Delta Details →	DEN 00:40 → ATL 05:42DL 302	3h 22m Atlanta	ATL 09:04 → BUF 11:09DL 1384	8h 29m	100%	86%
Delta Details →	DEN 23:59 → JFK 05:48DL 758	2h 12m New York	JFK 08:00 → BUF 09:41 +1DL 5223 · flown by Endeavor	7h 42m	100%	85%
Southwest Details →	DEN 23:50 → BWI 05:15WN 1501	1h 40m Baltimore	BWI 06:55 → BUF 08:10 +1WN 4566	6h 20m	98%	84%
American Details →	DEN 23:55 → PHL 05:32AA 2500	3h 12m Philadelphia	PHL 08:44 → BUF 10:18 +1AA 5925 · flown by Piedmont	8h 22m	93%	84%
United Details →	DEN 23:59 → EWR 05:40UA 1745	2h 45m Newark	EWR 08:25 → BUF 09:53 +1UA 3529 · flown by Republic	7h 54m	99%	83%
Delta Details →	DEN 05:45 → ATL 10:42DL 341	3h 18m Atlanta	ATL 14:00 → BUF 16:06DL 2266	8h 21m	99%	80%
Tight connection: often missed
American Details →	DEN 15:13 → PHL 20:59AA 1759	1h 21m Philadelphia	PHL 22:20 → BUF 23:53AA 5911 · flown by Piedmont	6h 40m	67%	53%
JetBlue Details →	DEN 10:24 → BOS 16:25B6 494	1h 15m Boston	BOS 17:40 → BUF 19:19B6 1115	6h 55m	75%	50%

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

IAD · 1h 18m · leaves 06:13 6%

DTW · 1h 19m · leaves 00:59 6%

Afternoon and evening

IAD · 1h 15m · leaves 15:40 19%

ORD · 1h 12m · leaves 13:25 21%

BOS · 1h 15m · leaves 10:24 25%

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.


United UA 1214 DEN 23:59 → PHL American AA 5925 PHL 08:44 → BUF Connection details →	3h 13m	8h 18m	98%	91%
United UA 2656 DEN 23:59 → BOS American AA 4666 BOS 09:03 → BUF Connection details →	3h 05m	8h 53m	100%	90%
Frontier F9 2746 DEN 23:59 → TPA Southwest WN 484 TPA 08:55 → BUF Connection details →	3h 23m	9h 36m	97%	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