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 4 in 5 on time.

Nonstops (seasonal or thin)


United	GSP	DEN	3h 40m	82%	1.1%	364	Flying now
Southwest	GSP	DEN	–	0%few flights	0.0%	2	Not flying now

Best connections, any airlines

Most reliable Quickest (80%+ on time)

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


United Details →	GSP 06:10 → ORD 07:30UA 4728 · flown by SkyWest	3h 24m Chicago	ORD 10:54 → DEN 12:45UA 581	8h 35m	97%	95%
Southwest + Unitedtwo ticketsDetails →	GSP 07:00 → BNA 07:10WN 4705	3h 16m Nashville	BNA 10:26 → DEN 12:23UA 502	7h 23m	100%	92%
United Details →	GSP 17:10 → IAH 18:45UA 4038 · flown by Mesa	3h 25m Houston	IAH 22:10 → DEN 23:57UA 1066	8h 47m	99%	88%
Delta + Unitedtwo ticketsDetails →	GSP 06:45 → ATL 07:49DL 1146	3h 21m Atlanta	ATL 11:10 → DEN 12:28UA 1327	7h 43m	97%	87%
Delta Details →	GSP 08:52 → ATL 09:57DL 1619	2h 53m Atlanta	ATL 12:50 → DEN 14:04DL 957	7h 12m	99%	86%
American + Unitedtwo ticketsDetails →	GSP 08:14 → ORD 09:31AA 3564 · flown by Envoy	3h 25m Chicago	ORD 12:56 → DEN 14:46UA 1150	8h 32m	100%	84%
United Details →	GSP 07:00 → IAH 08:33UA 4049 · flown by Mesa	4h 00m Houston	IAH 12:33 → DEN 14:17UA 2168	9h 17m	97%	84%
Delta + Unitedtwo ticketsDetails →	GSP 06:00 → LGA 07:59DL 5171 · flown by Endeavor	2h 01m New York	LGA 10:00 → DEN 12:20UA 716	8h 20m	93%	82%
Tight connection: often missed
American Details →	GSP 06:15 → MIA 08:11AA 3806 · flown by Envoy	46m Miami	MIA 08:57 → DEN 11:19AA 1739	7h 04m	73%	69%
United Details →	GSP 17:43 → ORD 19:00UA 5524 · flown by SkyWest	1h 00m Chicago	ORD 20:00 → DEN 22:01UA 767	6h 18m	61%	40%
American Details →	GSP 14:29 → PHL 16:29AA 6132 · flown by Piedmont	1h 01m Philadelphia	PHL 17:30 → DEN 19:45AA 3158	7h 16m	67%	40%

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

CLT · 1h 05m · leaves 09:04 5%

IAH · 59m · leaves 07:00 13%

MIA · 46m · leaves 06:15 27%

Afternoon and evening

DFW · 1h 01m · leaves 20:00 37%

ORD · 1h 00m · leaves 17:43 39%

DTW · 48m · leaves 18:55 42%

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