Flight number record
UA 303
United Airlines · Kansas City to Chicago
- Route
- MCI → ORD
- Departs
- 08:00
- Flights
- 364
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s UA 303, check with United Airlines.
UA 303 sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 6 points worse than the national rate of 77.3%. The late ones land a little over an hour behind schedule. That rests on 364 flights, with a median arrival 2 minutes late.
The national on-time rate over the same period is 77.3%, so UA 303 runs 6 points behind the country as a whole. Across a thousand flights that is about 64 extra late arrivals.
Key figures
On time
70.9%
Arrivals under 15 minutes late, of 357 completed flights
Avg delay
81 min
Across delayed arrivals only, not all flights
Cancelled
1.92%
National rate is 1.89%
1 hour+ late
11.8%
National rate is 8.3%
These figures cover 364 flights between September 2025 and August 2026. Beyond the headline rate, 11.8% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When UA 303 flies
UA 303 flies MCI to ORD without a single fixed slot. Its most common scheduled departure was 08:00, used on 69 of 364 flights, with 18:41 (47 flights) and 15:22 (42 flights) next.
- Departs 08:0069 flights19.0%
- Departs 18:4147 flights12.9%
- Departs 15:2242 flights11.5%
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 08:00 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 83.9%, and UA 303 runs 13 points worse at 70.9%. 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
UA 303 next to MCI to ORD
Every carrier on MCI to ORD combined arrived on time 74.6% of the time across 4,280 flights, so UA 303 is 4 points behind it. United flew 1,502 flights on the same city pair under all its flight numbers, including this one, and those ran 75.6% on time. Across its whole network United Airlines managed 78.8%, which this flight trails by 8 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 303thin sample | 364 | 70.9% | 81 min | 1.92% | C |
| All United Airlines on MCI–ORD | 1,502 | 75.6% | 90 min | 2.26% | B |
| All carriers on MCI–ORD | 4,280 | 74.6% | 101 min | 2.94% | C |
| United Airlines, whole network | 830,825 | 78.8% | 73 min | 1.02% | B |
Across the year
UA 303 quarter by quarter
UA 303 did not run the same all year. Its best quarter was Jan–Mar 2026 at 79.5% on time and its weakest Jul–Sep 2026 at 54.2%, a swing of 25 points on roughly 73 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 flights63.3%
- Oct–Dec 202592 flights72.5%
- Jan–Mar 202690 flights79.5%
- Apr–Jun 202691 flights74.2%
- Jul–Sep 202661 flights54.2%
Scale runs 45% to 85%.
By weekday, UA 303 did best on Thursday at 78.4% on time and worst on Friday at 61.2%. Each day rests on about 52 flights, so a gap of 17 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late UA 303 runs when it is late
The 104 late arrivals split 35 under half an hour, 27 between 30 and 60 minutes, and 42 an hour or more.
- 15+ min early57 flights16.0%
- Within 15 min196 flights54.9%
- 15–29 min late35 flights9.8%
- 30–59 min late27 flights7.6%
- 1–2 hours late21 flights5.9%
- 2+ hours late21 flights5.9%
Scale runs 0% to 100%.
Share of 357 completed flights by arrival against schedule.
11 of 84 late departures made up the time and arrived on time, 13% of them. In the other direction, 31 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 UA 303
The latest arrival of the period was on 11 June 2026, 8 hours 53 minutes behind schedule; most of its delay minutes were filed as national airspace system delay. The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 11 June 2026 | 8 hours 53 minutes | National Airspace System |
| 7 December 2025 | 5 hours 56 minutes | Late-arriving aircraft |
| 29 November 2025 | 5 hours 32 minutes | National Airspace System |
| 1 December 2025 | 5 hours 19 minutes | Extreme weather |
| 10 June 2026 | 4 hours 41 minutes | National Airspace System |
Delay causes
Why UA 303 runs late
National Airspace System accounts for 44% of the 8,405 delay minutes carriers reported here, and the remaining four split what is left.
- 44%National Airspace System
- 44%Late-arriving aircraft
- 7%Extreme weather
- 6%Carrier
44% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 8,405 reported delay minutes here, that single category outweighs weather by 7 to one. The split is drawn from 8,405 delay minutes reported on UA 303.
Cancellations sit at 1.92% against a national 1.89%, which is ordinary. Diversions add another 0.00%.
Connections and routes
What a delay on this flight costs
11.8% 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 five other city pairs in the data, including ORD to IAH (37), ORD to BWI (35) and ORD to SLC (31), but none flew often enough under UA 303 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to MCI to ORD 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 UA 303
For a booking, read UA 303 as 70.9% on time with 1.92% cancelled over 364 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- MCI to ORD, every carrier and departure
- ORD to MCI, the return direction
- United Airlines 1491 on the same route83.8%
- Kansas City International (MCI) delay statistics
- Chicago O'Hare International (ORD) delay statistics
- United Airlines on-time record
- Every United 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 United 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.