Flight number record

OO 5140

SkyWest Airlines · Chicago to Hancock

Route: ORD → CMX
Departs: 21:25
Flights: 364
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s OO 5140, check with SkyWest Airlines. SkyWest Airlines flies under contract for larger airlines, so a ticket for this flight may show a different airline code and number.

OO 5140 draws a D−. Roughly one flight in three arrives at least 15 minutes late, and the typical late arrival is about 2.9 hours behind schedule. Build slack into anything you connect to. That rests on 364 flights, with a median arrival 3 minutes late.

The national on-time rate over the same period is 77.6%, so OO 5140 runs 15 points behind the country as a whole. Across a thousand flights that is about 149 extra late arrivals.

On time

62.7%

Arrivals under 15 minutes late, of 332 completed flights

Avg delay

173 min

Across delayed arrivals only, not all flights

Cancelled

6.59%

National rate is 1.81%

1 hour+ late

19.0%

National rate is 8.1%

These figures cover 364 flights between July 2025 and June 2026. Beyond the headline rate, 19.0% 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.

Schedule

When OO 5140 flies

OO 5140 flies ORD to CMX without a single fixed slot. Its most common scheduled departure was 21:25, used on 97 of 364 flights, with 21:18 (65 flights) and 21:39 (56 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 21:2597 flights26.6%
Departs 21:1865 flights17.9%
Departs 21:3956 flights15.4%

Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.

Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.

A 21:25 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.5%, and OO 5140 runs 8 points worse at 62.7%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.

Against the route

OO 5140 next to ORD to CMX

Every carrier on ORD to CMX combined arrived on time 68.5% of the time across 795 flights, so OO 5140 is 6 points behind it. Across its whole network SkyWest Airlines managed 79.0%, which this flight trails by 16 points.

OO 5140 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
OO 5140thin sample	364	62.7%	173 min	6.59%	D−
All SkyWest Airlines on ORD–CMX	795	68.5%	134 min	5.91%	C−
All carriers on ORD–CMX	795	68.5%	134 min	5.91%	C−
SkyWest Airlines, whole network	852,935	79.0%	88 min	1.77%	B

Across the year

OO 5140 quarter by quarter

OO 5140 did not run the same all year. Its best quarter was Oct–Dec 2025 at 68.6% on time and its weakest Jan–Mar 2026 at 54.3%, a swing of 14 points on roughly 91 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.

Jul–Sep 202592 flights62.8%
Oct–Dec 202591 flights68.6%
Jan–Mar 202690 flights54.3%
Apr–Jun 202691 flights64.6%

Scale runs 45% to 75%. Rows with fewer than 30 flights show a dash.

By weekday, OO 5140 ranged from 56.5% on Sunday to 68.0% on Tuesday. With about 52 flights behind each day, a spread of 12 points is inside normal variation, so the day you fly is not worth changing for this flight.

Delay causes

Why OO 5140 runs late

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 21,000 reported delay minutes.

Carrier
36%
Late-arriving aircraft
30%
Extreme weather
20%
National Airspace System
14%

Extreme weather accounts for 20% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the quarterly figures above are the more useful view of the risk. The national share is 6%, so this operation carries roughly 3.2 times the usual weather exposure. The split is drawn from 21,453 delay minutes reported on OO 5140.

Cancellations run at 6.59%, against 1.81% nationally. That is about one flight in fifteen 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 routes

What a delay on this flight costs

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 19.0% 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.

The same number turns up on one other city pair in the data, including GRB to CMX (1), but none flew often enough under OO 5140 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to ORD to CMX only.

One caution: this is a thin sample. 364 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 OO 5140

For a booking, the cancellation rate is the figure to plan around on OO 5140: 6.59% of its 364 scheduled flights did not operate. A late arrival costs about 2.9 hours, but a cancellation costs the day, so leave a later option open.

Where to go next

A flight number here means SkyWest Airlines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.

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