Carrier route record

OOORD→BUF

SkyWest Airlines · Chicago to Buffalo

Flights: 330
Period: July 2025 to June 2026
Share of route: 15%
Carriers: 5

Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with SkyWest Airlines.

SkyWest on ORD to BUF draws a C−. About one flight in three arrives at least 15 minutes late, and the typical late arrival is an hour and a half behind schedule. Build slack into anything you connect to. That rests on 330 flights. The strongest carrier on the route with a full sample, Envoy Air, flew 422 at 79.8% on time.

Envoy Air is the most reliable of the three carriers covered here at 79.8% on time across 422 flights.

On time

66.1%

Arrivals under 15 minutes late, of 313 completed flights

Avg delay

84 min

Across delayed arrivals only, not all flights

Cancelled

4.85%

National rate is 1.81%

Whole route

70.6%

Every carrier on ORD to BUF, 2,195 flights

These figures cover 330 flights between July 2025 and June 2026. Beyond the headline rate, 14.4% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.

Carrier by carrier

SkyWest against every carrier on ORD to BUF

SkyWest flew 330 of the 2,195 flights on ORD to BUF, about 15% of it. Its 66.1% on time is 5 points worse than the route as a whole, which runs 70.6%. Ranked by on-time rate it is number four of five carriers on the route, where the range runs from Envoy at 79.8% to American at 58.8%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The choice of carrier is not cosmetic here. Envoy Air arrives on time 79.8% of the time; American Airlines manages 58.8%. Sample sizes sit next to every figure, because a two-point gap across 476 flights means less than a ten-point one.

On-time performance by carrier on ORD to BUF
Airline	Flights	On time	Avg delay	Cancelled	Grade
Envoy Air	422	79.8%	60 min	2.61%	B
Republic Airwaysthin sample	355	74.3%	74 min	5.07%	C−
United Airlines	612	73.8%	81 min	1.14%	C
SkyWest Airlines (this page)thin sample	330	66.1%	84 min	4.85%	C−
American Airlines	476	58.8%	88 min	1.26%	D

The spread between Envoy and American is 21 points, wide enough that it should decide the booking. On a hundred trips that is 21 more arrivals inside the on-time window.

Departure window

When SkyWest runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 22 points, against 21 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am84 flights75.0%
8am–11am60 flights52.7%
11am–2pm49 flights68.8%
2pm–5pm122 flights67.0%
5pm–8pm15 flights—
8pm–5am—

Scale runs 45% to 80%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 75.0% of the time, against 52.7% for the morning window. That is 22 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 2pm–5pm window is the busiest, with 122 flights scheduled in it.

Across the year

SkyWest on ORD to BUF through the year

Jul–Sep 202516 flights—
Oct–Dec 2025122 flights66.1%
Jan–Mar 202689 flights57.8%
Apr–Jun 2026103 flights74.5%

Scale runs 50% to 80%. Rows with fewer than 30 flights show a dash.

Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 66.1% on time across 330 flights.

SkyWest on ORD to BUF did not run the same all year. Its best quarter was Apr–Jun 2026 at 74.5% on time and its weakest Jan–Mar 2026 at 57.8%, a swing of 17 points on roughly 110 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.

Across the week, Wednesday is the strongest day at 75.6% on time and Sunday the weakest at 50.0%. 26 points is a smaller lever than departure hour, but it is free.

Delay causes

Why SkyWest runs late on this route

Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 8,891 reported delay minutes.

Late-arriving aircraft
38%
Carrier
35%
National Airspace System
19%
Extreme weather
7%

38% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 8,891 reported delay minutes here, that single category outweighs weather by 5 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 8,891 reported delay minutes.

The largest share of delay minutes, 35%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 3,108 of the 8,891 delay minutes reported here.

Cancellations run at 4.85%, against 1.81% nationally. That is about one flight in twenty cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.

Connections and stage length

What a delay here costs

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 14.4% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.

At 474 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 5am–8am window matters as much as it does.

The return leg is a different operation and performs like one: it runs 60.2% on time across 330 flights, 6 points below this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 6 points of difference.

One caution: this is a thin sample. 330 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.

What to do with this

Booking SkyWest on ORD to BUF

Put together: the delay figures matter less here than the 4.85% cancellation rate. A late arrival costs you an hour and a half; a cancelled flight costs you the day. Book the 5am–8am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 313 completed flights over 12 months sit behind that.

Where to go next

Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures