Flight number record
UA 2040
United Airlines · Boston to Chicago
- Route
- BOS → ORD
- Departs
- 16:25
- Flights
- 360
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s UA 2040, check with United Airlines.
UA 2040 earns an F, which is as low as this site's scale goes for a reason. Only 53.1% of flights arrive inside the 15-minute window, 24 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 360 flights, with a median arrival 11 minutes late.
The national on-time rate over the same period is 77.3%, so UA 2040 runs 24 points behind the country as a whole. Across a thousand flights that is about 242 extra late arrivals.
Key figures
On time
53.1%
Arrivals under 15 minutes late, of 352 completed flights
Avg delay
72 min
Across delayed arrivals only, not all flights
Cancelled
2.22%
National rate is 1.89%
1 hour+ late
14.8%
National rate is 8.3%
These figures cover 360 flights between September 2025 and August 2026. Beyond the headline rate, 14.8% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When UA 2040 flies
UA 2040 flies BOS to ORD without a single fixed slot. Its most common scheduled departure was 16:25, used on 52 of 360 flights, with 16:15 (47 flights) and 17:00 (46 flights) next.
- Departs 16:2552 flights14.4%
- Departs 16:1547 flights13.1%
- Departs 17:0046 flights12.8%
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 16:25 departure sits in the 2pm–5pm window. Across every US flight scheduled in that window the on-time rate is 71.9%, and UA 2040 runs 19 points worse at 53.1%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.
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Against the route
UA 2040 next to BOS to ORD
Every carrier on BOS to ORD combined arrived on time 71.9% of the time across 7,860 flights, so UA 2040 is 19 points behind it. United flew 2,791 flights on the same city pair under all its flight numbers, including this one, and those ran 74.5% on time. Across its whole network United Airlines managed 78.8%, which this flight trails by 26 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 2040thin sample | 360 | 53.1% | 72 min | 2.22% | F |
| All United Airlines on BOS–ORD | 2,791 | 74.5% | 86 min | 1.79% | C |
| All carriers on BOS–ORD | 7,860 | 71.9% | 87 min | 2.98% | C |
| United Airlines, whole network | 830,825 | 78.8% | 73 min | 1.02% | B |
Across the year
UA 2040 quarter by quarter
UA 2040 did not run the same all year. Its best quarter was Apr–Jun 2026 at 62.2% on time and its weakest Jul–Sep 2025 at 40.0%, a swing of 22 points on roughly 72 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 flights40.0%
- Oct–Dec 202590 flights51.7%
- Jan–Mar 202689 flights52.4%
- Apr–Jun 202691 flights62.2%
- Jul–Sep 202660 flights49.2%
Scale runs 30% to 70%.
By weekday, UA 2040 did best on Tuesday at 68.6% on time and worst on Friday at 39.2%. Each day rests on about 51 flights, so a gap of 29 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late UA 2040 runs when it is late
The 165 late arrivals split 64 under half an hour, 49 between 30 and 60 minutes, and 52 an hour or more.
- 15+ min early30 flights8.5%
- Within 15 min157 flights44.6%
- 15–29 min late64 flights18.2%
- 30–59 min late49 flights13.9%
- 1–2 hours late25 flights7.1%
- 2+ hours late27 flights7.7%
Scale runs 0% to 100%.
Share of 352 completed flights by arrival against schedule.
Time lost at the gate mostly stays lost. Of 73 departures that left 15 minutes late or more, only 2 made it up before arrival. In the other direction, 94 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 2040
The latest arrival of the period was on 3 July 2026, 19 hours 32 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). On three of the five worst days the largest share was filed as national airspace system delay.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 3 July 2026 | 19 hours 32 minutes | Carrier |
| 21 July 2026 | 6 hours | Carrier |
| 18 May 2026 | 4 hours 57 minutes | National Airspace System |
| 10 June 2026 | 4 hours 47 minutes | National Airspace System |
| 9 November 2025 | 4 hours 19 minutes | National Airspace System |
Delay causes
Why UA 2040 runs late
National Airspace System accounts for 56% of the 12,000 delay minutes carriers reported here, and the remaining four split what is left.
- 56%National Airspace System
- 21%Late-arriving aircraft
- 20%Carrier
- 3%Extreme weather
56% 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 6,554 minutes out of 12,000, against a national NAS share of 21%. The split is drawn from 11,790 delay minutes reported on UA 2040.
Cancellations sit at 2.22% against a national 1.89%, which is ordinary. Diversions add another 0.00%.
Connections and routes
What a delay on this flight costs
14.8% 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 867 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 four other city pairs in the data, including ORD to SFO (14), ORD to FLL (2) and ORD to PHX (2), but none flew often enough under UA 2040 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to BOS to ORD only.
One caution: this is a thin sample. 360 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 2040
For a booking, UA 2040 is a flight to put a long connection behind. 14.8% of its completed flights arrived an hour or more late, which a short layover will not absorb. If the onward flight is on a separate ticket, the risk sits with you.
Related
Where to go next
- BOS to ORD, every carrier and departure
- ORD to BOS, the return direction
- United Airlines 1414 on the same route93.6%
- United Airlines 1732 on the same route83.8%
- United Airlines 1349 on the same route86.0%
- United Airlines 1015 on the same route50.3%
- JetBlue Airways 311 on the same route79.1%
- Delta Air Lines 2570 on the same route80.5%
- Boston Logan International (BOS) 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
- How often a connection fails at the major US hubs
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.