Flight number record
UA 2040
United Airlines · Boston to Chicago
- Route
- BOS → ORD
- Departs
- 16:27
- Flights
- 361
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 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 52.3% of flights arrive inside the 15-minute window, 25 points worse than the national rate of 77.6%. Late arrivals average about an hour. Treat any tight connection here as a coin flip. That rests on 361 flights, with a median arrival 11 minutes late.
The national on-time rate over the same period is 77.6%, so UA 2040 runs 25 points behind the country as a whole. Across a thousand flights that is about 253 extra late arrivals.
Key figures
On time
52.3%
Arrivals under 15 minutes late, of 352 completed flights
Avg delay
62 min
Across delayed arrivals only, not all flights
Cancelled
2.49%
National rate is 1.81%
1 hour+ late
14.2%
National rate is 8.1%
These figures cover 361 flights between July 2025 and June 2026. Beyond the headline rate, 14.2% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Schedule
When UA 2040 flies
UA 2040 flies BOS to ORD without a single fixed slot. Its most common scheduled departure was 16:27, used on 85 of 361 flights, with 16:25 (52 flights) and 16:15 (47 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 16:2785 flights23.5%
- Departs 16:2552 flights14.4%
- Departs 16:1547 flights13.0%
Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 16:27 departure sits in the 2pm–5pm window. Across every US flight scheduled in that window the on-time rate is 72.4%, and UA 2040 runs 20 points worse at 52.3%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.
Against the route
UA 2040 next to BOS to ORD
Every carrier on BOS to ORD combined arrived on time 72.7% of the time across 7,637 flights, so UA 2040 is 20 points behind it. United flew 2,678 flights on the same city pair under all its flight numbers, including this one, and those ran 75.0% on time. Across its whole network United Airlines managed 79.0%, which this flight trails by 27 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 2040thin sample | 361 | 52.3% | 62 min | 2.49% | F |
| All United Airlines on BOS–ORD | 2,678 | 75.0% | 85 min | 1.90% | B |
| All carriers on BOS–ORD | 7,637 | 72.7% | 84 min | 2.91% | C |
| United Airlines, whole network | 821,041 | 79.0% | 72 min | 1.01% | 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 42.7%, a swing of 20 points on roughly 90 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 202591 flights42.7%
- Oct–Dec 202590 flights51.7%
- Jan–Mar 202689 flights52.4%
- Apr–Jun 202691 flights62.2%
Scale runs 35% to 70%. Rows with fewer than 30 flights show a dash.
By weekday, UA 2040 did best on Tuesday at 65.4% on time and worst on Friday at 42.0%. Each day rests on about 52 flights, so a gap of 23 points is worth noticing but could still narrow in another year.
Delay causes
Why UA 2040 runs late
One category carries most of the weight here. National Airspace System accounts for 64% of the 10,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 64%National Airspace System
- 25%Late-arriving aircraft
- 7%Carrier
- 5%Extreme weather
64% 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 6,677 minutes out of 10,000, against a national NAS share of 21%. The split is drawn from 10,478 delay minutes reported on UA 2040.
Cancellations sit at 2.49% against a national 1.81%, which is ordinary. Diversions add another 0.00%.
Connections and routes
What a delay on this flight costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 14.2% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum 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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The same number turns up on four other city pairs in the data, including ORD to MCI (30), ORD to DEN (18) and ORD to FLL (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. 361 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. 14.2% 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 1732 on the same route84.5%
- United Airlines 1414 on the same route94.2%
- United Airlines 1015 on the same route48.8%
- JetBlue Airways 311 on the same route84.3%
- Delta Air Lines 2646 on the same route60.3%
- Delta Air Lines 2570 on the same route80.0%
- 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.