Flight number record
UA 661
United Airlines · Newark to Chicago
- Route
- EWR → ORD
- Departs
- 16:45
- Flights
- 346
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s UA 661, check with United Airlines.
UA 661 earns an F−, which is as low as this site's scale goes for a reason. Only 47.6% of flights arrive inside the 15-minute window, 30 points worse than the national rate of 77.3%. Late arrivals average a little over an hour. Treat any tight connection here as a coin flip. That rests on 346 flights, with a median arrival 16 minutes late.
The national on-time rate over the same period is 77.3%, so UA 661 runs 30 points behind the country as a whole. Across a thousand flights that is about 297 extra late arrivals.
Key figures
On time
47.6%
Arrivals under 15 minutes late, of 330 completed flights
Avg delay
76 min
Across delayed arrivals only, not all flights
Cancelled
4.34%
National rate is 1.89%
1 hour+ late
19.1%
National rate is 8.3%
These figures cover 346 flights between September 2025 and August 2026. Beyond the headline rate, 19.1% 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 UA 661 flies
UA 661 flies EWR to ORD without a single fixed slot. Its most common scheduled departure was 16:45, used on 149 of 346 flights, with 16:50 (50 flights) and 16:49 (42 flights) next.
- Departs 16:45149 flights43.1%
- Departs 16:5050 flights14.5%
- Departs 16:4942 flights12.1%
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 16:45 departure sits in the 2pm–5pm window. Across every US flight scheduled in that window the on-time rate is 71.9%, and UA 661 runs 24 points worse at 47.6%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.
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
UA 661 next to EWR to ORD
Every carrier on EWR to ORD combined arrived on time 70.7% of the time across 6,123 flights, so UA 661 is 23 points behind it. United flew 4,415 flights on the same city pair under all its flight numbers, including this one, and those ran 70.3% on time. Across its whole network United Airlines managed 78.8%, which this flight trails by 31 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 661thin sample | 346 | 47.6% | 76 min | 4.34% | F− |
| All United Airlines on EWR–ORD | 4,415 | 70.3% | 80 min | 2.83% | C |
| All carriers on EWR–ORD | 6,123 | 70.7% | 85 min | 3.90% | C− |
| United Airlines, whole network | 830,825 | 78.8% | 73 min | 1.02% | B |
Across the year
UA 661 quarter by quarter
UA 661 did not run the same all year. Its best quarter was Jul–Sep 2025 at 60.0% on time and its weakest Jul–Sep 2026 at 36.5%, a swing of 24 points on roughly 69 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 flights60.0%
- Oct–Dec 202575 flights48.6%
- Jan–Mar 202690 flights43.7%
- Apr–Jun 202690 flights52.9%
- Jul–Sep 202661 flights36.5%
Scale runs 30% to 65%.
By weekday, UA 661 did best on Saturday at 59.2% on time and worst on Monday at 34.8%. Each day rests on about 49 flights, so a gap of 24 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late UA 661 runs when it is late
The 173 late arrivals split 49 under half an hour, 61 between 30 and 60 minutes, and 63 an hour or more.
- 15+ min early26 flights7.9%
- Within 15 min131 flights39.7%
- 15–29 min late49 flights14.8%
- 30–59 min late61 flights18.5%
- 1–2 hours late31 flights9.4%
- 2+ hours late32 flights9.7%
Scale runs 0% to 100%.
Share of 330 completed flights by arrival against schedule.
Time lost at the gate mostly stays lost. Of 103 departures that left 15 minutes late or more, only 5 made it up before arrival. In the other direction, 75 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 661
The latest arrival of the period was on 29 November 2025, 7 hours 58 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 |
|---|---|---|
| 29 November 2025 | 7 hours 58 minutes | National Airspace System |
| 27 April 2026 | 7 hours 50 minutes | Late-arriving aircraft |
| 11 June 2026 | 6 hours 50 minutes | National Airspace System |
| 6 March 2026 | 6 hours 47 minutes | Carrier |
| 4 July 2026 | 5 hours 2 minutes | National Airspace System |
Delay causes
Why UA 661 runs late
National Airspace System accounts for 53% of the 13,000 delay minutes carriers reported here, and the remaining four split what is left.
- 53%National Airspace System
- 24%Carrier
- 21%Late-arriving aircraft
- 1%Extreme weather
53% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 7,055 minutes out of 13,000, against a national NAS share of 21%. The split is drawn from 13,194 delay minutes reported on UA 661.
Cancellations run at 4.34%, against 1.89% nationally. That is about one flight in 25 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
19.1% 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 719 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty.
The same number turns up on nine other city pairs in the data, including ORD to LAX (199), SNA to EWR (178) and ORD to FAT (26), but none flew often enough under UA 661 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to EWR to ORD only.
One caution: this is a thin sample. 346 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 661
For a booking, the cancellation rate is the figure to plan around on UA 661: 4.34% of its 346 scheduled flights did not operate. A late arrival costs a little over an hour, but a cancellation costs the day, so leave a later option open.
Related
Where to go next
- EWR to ORD, every carrier and departure
- ORD to EWR, the return direction
- United Airlines 1525 on the same route77.1%
- United Airlines 1875 on the same route77.7%
- United Airlines 546 on the same route66.6%
- United Airlines 254 on the same route43.5%
- Newark Liberty International (EWR) 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
- The best time of day to fly, according to 7.05 million flight records
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.