Flight number record
OO 4791
SkyWest Airlines · Chicago to South Bend
- Route
- ORD → SBN
- Departs
- 10:35
- Flights
- 314
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s OO 4791, 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 4791 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 314 flights, with a median arrival 1 minute early.
The national on-time rate over the same period is 77.3%, so OO 4791 runs 12 points behind the country as a whole. Across a thousand flights that is about 117 extra late arrivals.
Key figures
On time
65.6%
Arrivals under 15 minutes late, of 305 completed flights
Avg delay
97 min
Across delayed arrivals only, not all flights
Cancelled
2.87%
National rate is 1.89%
1 hour+ late
15.1%
National rate is 8.3%
These figures cover 314 flights between September 2025 and August 2026. Beyond the headline rate, 15.1% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
Fare search by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Schedule
When OO 4791 flies
OO 4791 flies ORD to SBN without a single fixed slot. Its most common scheduled departure was 10:35, used on 188 of 314 flights, with 10:25 (56 flights) and 10:30 (53 flights) next.
- Departs 10:35188 flights59.9%
- Departs 10:2556 flights17.8%
- Departs 10:3053 flights16.9%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 10:35 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 83.9%, and OO 4791 runs 18 points worse at 65.6%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Against the route
OO 4791 next to ORD to SBN
Every carrier on ORD to SBN combined arrived on time 63.1% of the time across 2,789 flights, so OO 4791 is 2 points ahead of it. SkyWest flew 2,777 flights on the same city pair under all its flight numbers, including this one, and those ran 63.0% on time. Across its whole network SkyWest Airlines managed 78.7%, which this flight trails by 13 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| OO 4791thin sample | 314 | 65.6% | 97 min | 2.87% | C |
| All SkyWest Airlines on ORD–SBN | 2,777 | 63.0% | 87 min | 4.39% | D− |
| All carriers on ORD–SBN | 2,789 | 63.1% | 87 min | 4.37% | D− |
| SkyWest Airlines, whole network | 855,406 | 78.7% | 88 min | 1.79% | B |
Across the year
OO 4791 quarter by quarter
Quarter by quarter OO 4791 held fairly steady: 66.7% in Oct–Dec 2025, 57.1% in Jan–Mar 2026 and 65.5% in Apr–Jun 2026. A spread of 10 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.
- Jul–Sep 202530 flights—
- Oct–Dec 202590 flights66.7%
- Jan–Mar 202688 flights57.1%
- Apr–Jun 202685 flights65.5%
- Jul–Sep 202621 flights—
Scale runs 50% to 70%. Rows with fewer than 30 flights show a dash.
By weekday, OO 4791 did best on Thursday at 83.3% on time and worst on Saturday at 58.1%. Each day rests on about 45 flights, so a gap of 25 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late OO 4791 runs when it is late
OO 4791 often beats the schedule: 84 of 305 completed flights, 28%, arrived 15 minutes or more early. The 105 late arrivals split 33 under half an hour, 26 between 30 and 60 minutes, and 46 an hour or more.
- 15+ min early84 flights27.5%
- Within 15 min116 flights38.0%
- 15–29 min late33 flights10.8%
- 30–59 min late26 flights8.5%
- 1–2 hours late21 flights6.9%
- 2+ hours late25 flights8.2%
Scale runs 0% to 100%.
Share of 305 completed flights by arrival against schedule.
Time lost at the gate mostly stays lost. Of 75 departures that left 15 minutes late or more, only 3 made it up before arrival. In the other direction, 33 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at SBN.
The worst days
Worst days for OO 4791
The latest arrival of the period was on 29 December 2025, 9 hours 46 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 29 December 2025 | 9 hours 46 minutes | Late-arriving aircraft |
| 9 November 2025 | 8 hours 18 minutes | National Airspace System |
| 25 January 2026 | 8 hours 6 minutes | Carrier |
| 26 November 2025 | 6 hours 36 minutes | Late-arriving aircraft |
| 26 January 2026 | 6 hours 26 minutes | Late-arriving aircraft |
Delay causes
Why OO 4791 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 10,000 reported delay minutes.
- 35%Late-arriving aircraft
- 32%Carrier
- 27%National Airspace System
- 6%Extreme weather
35% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 10,000 reported delay minutes here, that single category outweighs weather by 6 to one. The split is drawn from 10,187 delay minutes reported on OO 4791.
Cancellations run at 2.87%, against 1.89% nationally. That is roughly one flight in 30 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
15.1% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection 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 ORD to BDL (47), but none flew often enough under OO 4791 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to ORD to SBN only.
One caution: this is a thin sample. 314 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 4791
For a booking, the cancellation rate is the figure to plan around on OO 4791: 2.87% of its 314 scheduled flights did not operate. A late arrival costs an hour and a half, but a cancellation costs the day, so leave a later option open.
Related
Where to go next
- ORD to SBN, every carrier and departure
- SBN to ORD, the return direction
- SkyWest Airlines 5499 on the same route58.5%
- SkyWest Airlines 5274 on the same route67.0%
- SkyWest Airlines 5505 on the same route62.3%
- SkyWest Airlines 4636 on the same route52.4%
- SkyWest Airlines 5887 on the same route66.1%
- Chicago O'Hare International (ORD) delay statistics
- SkyWest Airlines on-time record
- Every SkyWest Airlines flight number with a record
- The most and least reliable flight numbers in the US
- Why the first flight of the morning is statistically safest
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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.