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

No clear winner: United’s IAD → BUF flights land within a few points of 4 in 5 on time whatever the hour.

Nonstops


United	IAD	BUF	1h 27m	81%	2.5%	1,150	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. Layovers up to 4 hours. Pick a connection for the details.


American Details →	IAD 06:33 → CLT 08:00AA 1216	3h 10m Charlotte	CLT 11:10 → BUF 12:54AA 1616	6h 22m	97%	84%
Delta Details →	IAD 06:00 → ATL 07:46DL 2127	1h 18m Atlanta	ATL 09:04 → BUF 11:09DL 1384	5h 09m	94%	80%
Delta Details →	IAD 11:44 → MSP 13:39DL 3699 · flown by SkyWest	1h 43m Minneapolis	MSP 15:22 → BUF 18:27DL 1749	6h 43m	95%	80%
Delta Details →	IAD 08:27 → ATL 10:17DL 3080	3h 43m Atlanta	ATL 14:00 → BUF 16:06DL 2266	7h 39m	98%	79%
United Details →	IAD 10:31 → ORD 11:53UA 1252	2h 02m Chicago	ORD 13:55 → BUF 16:41UA 2226	6h 10m	98%	79%
Delta Details →	IAD 06:00 → DTW 07:40DL 3826 · flown by SkyWest	2h 25m Detroit	DTW 10:05 → BUF 11:24DL 3636 · flown by SkyWest	5h 24m	96%	75%
United Details →	IAD 12:35 → EWR 14:01UA 1498	2h 36m Newark	EWR 16:37 → BUF 18:05UA 3607 · flown by Republic	5h 30m	96%	71%
United Details →	IAD 06:10 → ORD 07:27UA 2070	2h 58m Chicago	ORD 10:25 → BUF 13:13UA 4382 · flown by GoJet	7h 03m	100%	71%
Tight connection: often missed
United Details →	IAD 08:15 → ORD 09:36UA 1775	49m Chicago	ORD 10:25 → BUF 13:13UA 4382 · flown by GoJet	4h 58m	69%	49%
United Details →	IAD 15:39 → ORD 17:02UA 1393	1h 15m Chicago	ORD 18:17 → BUF 21:08UA 5763 · flown by SkyWest	5h 29m	72%	42%

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

ATL · 1h 18m · leaves 06:00 6%

ORD · 49m · leaves 08:15 31%

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 641 IAD 08:35 → BOS American AA 4440 BOS 13:55 → BUF Connection details →	3h 35m	7h 09m	100%	87%
United UA 2739 IAD 08:15 → ATL Delta DL 2266 ATL 14:00 → BUF Connection details →	3h 46m	7h 51m	98%	80%
United UA 4015 IAD 08:35 → PHL American AA 6041 PHL 12:50 → BUF Connection details →	3h 05m	5h 44m	100%	74%

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