Flight number record
OO 4803
SkyWest Airlines · Milwaukee to Chicago
- Route
- MKE → ORD
- Departs
- 07:00
- Flights
- 342
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s OO 4803, 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 4803 lands a B, level with the national rate of 77.3%. About one flight in four arrives 15 minutes late or worse, and those flights are late by about 2.1 hours on average. That rests on 342 flights, with a median arrival 5 minutes early.
Key figures
On time
76.6%
Arrivals under 15 minutes late, of 334 completed flights
Avg delay
127 min
Across delayed arrivals only, not all flights
Cancelled
2.34%
National rate is 1.89%
1 hour+ late
11.7%
National rate is 8.3%
These figures cover 342 flights between September 2025 and August 2026. Beyond the headline rate, 11.7% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When OO 4803 flies
OO 4803 flies MKE to ORD without a single fixed slot. Its most common scheduled departure was 07:00, used on 188 of 342 flights, with 07:50 (41 flights) next.
- Departs 07:00188 flights55.0%
- Departs 07:5041 flights12.0%
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 07:00 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and OO 4803 runs 13 points worse at 76.6%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
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Against the route
OO 4803 next to MKE to ORD
Every carrier on MKE to ORD combined arrived on time 68.4% of the time across 5,344 flights, so OO 4803 is 8 points ahead of it. SkyWest flew 5,046 flights on the same city pair under all its flight numbers, including this one, and those ran 68.3% on time. Across its whole network SkyWest Airlines managed 78.7%, which this flight trails by 2 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| OO 4803thin sample | 342 | 76.6% | 127 min | 2.34% | B |
| All SkyWest Airlines on MKE–ORD | 5,046 | 68.3% | 94 min | 4.22% | C− |
| All carriers on MKE–ORD | 5,344 | 68.4% | 93 min | 4.38% | C− |
| SkyWest Airlines, whole network | 855,406 | 78.7% | 88 min | 1.79% | B |
Across the year
OO 4803 quarter by quarter
OO 4803 did not run the same all year. Its best quarter was Apr–Jun 2026 at 83.0% on time and its weakest Jul–Sep 2026 at 62.5%, a swing of 21 points on roughly 68 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 202530 flights76.7%
- Oct–Dec 202591 flights77.8%
- Jan–Mar 202689 flights75.6%
- Apr–Jun 202691 flights83.0%
- Jul–Sep 202641 flights62.5%
Scale runs 55% to 90%.
By weekday, OO 4803 ranged from 72.9% on Sunday to 83.0% on Thursday. With about 49 flights behind each day, a spread of 10 points is inside normal variation, so the day you fly is not worth changing for this flight.
Arrival by arrival
How late OO 4803 runs when it is late
OO 4803 often beats the schedule: 94 of 334 completed flights, 28%, arrived 15 minutes or more early. The 78 late arrivals split 23 under half an hour, 16 between 30 and 60 minutes, and 39 an hour or more.
- 15+ min early94 flights28.1%
- Within 15 min162 flights48.5%
- 15–29 min late23 flights6.9%
- 30–59 min late16 flights4.8%
- 1–2 hours late18 flights5.4%
- 2+ hours late21 flights6.3%
Scale runs 0% to 100%.
Share of 334 completed flights by arrival against schedule.
9 of 55 late departures made up the time and arrived on time, 16% of them. In the other direction, 32 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 ORD.
The worst days
Worst days for OO 4803
The latest arrival of the period was on 23 September 2025, 15 hours 1 minute behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on four of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 23 September 2025 | 15 hours 1 minute | Carrier |
| 13 September 2025 | 8 hours 15 minutes | Extreme weather |
| 14 April 2026 | 7 hours 29 minutes | Carrier |
| 14 June 2026 | 7 hours 1 minute | Carrier |
| 31 March 2026 | 6 hours 46 minutes | Carrier |
Delay causes
Why OO 4803 runs late
Carrier accounts for 65% of the 9,895 delay minutes carriers reported here, and the remaining four split what is left.
- 65%Carrier
- 16%Late-arriving aircraft
- 9%National Airspace System
- 9%Extreme weather
The largest share of delay minutes, 65%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 6,463 of the 9,895 delay minutes reported here. The split is drawn from 9,895 delay minutes reported on OO 4803.
Cancellations sit at 2.34% against a national 1.89%, which is ordinary. Diversions add another 0.00%.
Connections and routes
What a delay on this flight costs
11.7% 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 IAH to GRR (21), but none flew often enough under OO 4803 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to MKE to ORD only.
One caution: this is a thin sample. 342 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 4803
For a booking, read OO 4803 as 76.6% on time with 2.34% cancelled over 342 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- MKE to ORD, every carrier and departure
- ORD to MKE, the return direction
- SkyWest Airlines 5402 on the same route75.1%
- SkyWest Airlines 5799 on the same route76.4%
- SkyWest Airlines 4740 on the same route67.3%
- SkyWest Airlines 5648 on the same route52.3%
- Milwaukee Mitchell International (MKE) delay statistics
- 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
- The best time of day to fly, according to 7.05 million flight records
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.