Flight profile · United Airlines
UA2040
Boston (BOS) to Chicago (ORD) · scheduled 4:27 PM – 6:20 PM
How UA2040 performs
738 operations, June 2024 – July 2026.
UA2040 arrived on time 58.0% of the time, against 76.9% for all BOS → ORD flights, so this departure is 18.9 percentage points worse than the route as a whole. Against United Airlines’ own flights on this route it is 21.0 points worse.
Source: US DOT Bureau of Transportation Statistics · 738 operations, June 2024 – July 2026 · If UA2040 is cancelled or significantly changed, DOT’s automatic refund rule may entitle you to your money back. The refund checker walks through eligibility.
What stands out
How UA2040 compares to other flight numbers, not just to itself.
This flight runs unusually far behind the carrier's own average on this route, worse than 98% of 11,589 comparable flight numbers.
58.0% on time for this specific departure, against 79.0% for the same carrier's other flights on this route.
Source: FlyerIntel analysis of US DOT BTS data · June 2024 – July 2026 · The one thing about this specific departure that ranks most extreme against every other published flight number, out of everything FlyerIntel checks — shown only when something clears a real statistical bar, not for every flight.
Where UA2040 is right now
A live reading, only if you ask for it. It is not part of the reliability record above.
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Against the rest of the route
| Flight or route | On time | Cancelled | Median delay | Severe | Flights |
|---|---|---|---|---|---|
| UA2040 | 58.0% | 1.76% | 9 min | 12.0% | 738 |
| United Airlines on BOS → ORD | 79.0% | 1.56% | -6 min | 8.3% | 7,613 |
| All BOS → ORD flights | 76.9% | 2.02% | -7 min | 9.9% | 21,884 |
Source: FlyerIntel analysis of US DOT BTS data · June 2024 – July 2026
Why UA2040 runs late
Where US DOT attributed the delay minutes on this flight.
airspace and airport capacity, including weather-driven flow control
the inbound aircraft was late, so this flight started late
crew, maintenance, boarding and fueling, all within the carrier’s control
weather severe enough to stop this flight specifically
Share of the delay minutes US DOT attributed to each cause for UA2040 on BOS → ORD. Only delays of 15 minutes or more are attributed.
Source: US DOT Bureau of Transportation Statistics · Data covering June 2024 – July 2026
Does a late aircraft delay this flight?
How often the plane that flies UA2040 comes in late, and what that does to the departure.
When the aircraft came in 15 or more minutes late, UA2040 pushed back an average of 34 minutes late; when it came in on time or early, an average of 8 minutes late.
Each departure is matched to the flight the same aircraft flew into BOS just before it, using the tail number in the DOT file, 713 of 727 departures in all. A departure is left out when that flight is unknown, was cancelled or diverted, or the aircraft had sat for more than 12 hours. A flight the airline cancelled never left and is not in the count, and one flown by a substitute aircraft is matched to the aircraft that flew it, not to the one first planned.
Against the network at the same turn length
| Share of departures | Inbound landed 15+ late | Left 15+ late after a late inbound | Left 15+ late after an on-time inbound |
|---|---|---|---|
| UA2040 | 23% | 44% | 9% |
| Network, same turn | 23% | 40% | 9% |
The schedule leaves a long gap on the ground, which gives a late aircraft room to catch up before this flight pushes back.
The network row is every flight with a scheduled turn of 90 minutes to 3 hours. How often UA2040’s aircraft landed 15 or more minutes late is about the same as the network’s and, once the aircraft was late, how often UA2040 left 15 or more minutes late is higher than the network’s.
More: Which Flight Numbers Pay for a Late Aircraft lists the flight numbers that pass a late aircraft on.
Source: US DOT Bureau of Transportation Statistics · Data covering June 2024 – July 2026
From pushback to gate
When it leaves BOS late, does that still matter by the time it reaches ORD?
UA2040 pushes back an average of 15.7 minutes late and arrives a further 9.3 minutes behind that. This departure loses ground between the two gates rather than recovering it, so a late pushback here tends to get worse on the way, not better. It spends 20.7 minutes on the taxiways at BOS, 1.6 minutes shorter than a typical BOS departure in the same hour.
On arrival at ORD, UA2040 spends 29.9 min taxiing from touchdown to the gate — ground time a connecting passenger sits through before they can even leave the aircraft, on top of however late the flight itself ran. That is 12.1 minutes longer than a typical ORD arrival (17.8 min).
Departure delay is averaged over every pushback and arrival delay over every completed arrival, so the two counts differ by the flights that never reached ORD. Taxi-out is gate to wheels up and sits inside the scheduled block rather than on top of it; the comparison is 26,869 departures from BOS scheduled in the clock hour UA2040 most often leaves in. Taxi-in is landing to gate, compared against every arrival FlyerIntel has on file at ORD (952,666 flights), not just UA2040’s own. More on taxi time.
Source: FlyerIntel analysis of US DOT BTS data · June 2024 – July 2026
The hour it leaves BOS
Part of any flight’s record belongs to the clock rather than to the flight. UA2040 has one departure time, so this is what that time is worth.
On-time arrival rate. 26,869 departures from BOS are scheduled in the 4 PM–5 PM hour over the period, against 440,893 across the whole day.
UA2040 is scheduled out of BOS at 4:27 PM, in the 4 PM–5 PM bank. Departures from BOS in that hour arrive on time 66.6% of the time against 77.2% across the airport’s whole day — the slot alone is worth 10.6 points worse before anything about this particular flight is considered.
The two airport figures cover every departure from BOS to every destination, so they describe the slot rather than this journey — the like-for-like comparison against the route is above. Hours are scheduled local, and a number whose schedule moved between banks inside the period has no single hour and is not described here at all. Why the hour matters.
Source: FlyerIntel analysis of US DOT BTS data · June 2024 – July 2026 · Hours below 120 departures are not scored.
Other routes UA2040 has flown
A flight number is a slot in a schedule, and carriers reassign it. These are the other city pairs this number served in the analysis period.
| Route | Operated | Flights | On time |
|---|---|---|---|
| ORD→FLL Chicago to Fort Lauderdale | December 27, 2025 – January 3, 2026 | 2 | — |
| ORD→PHX Chicago to Phoenix | November 29–30, 2025 | 2 | — |
| ORD→DEN Chicago to Denver | May 1, 2025 – August 18, 2025 | 74 | — |
| ORD→MCI Chicago to Kansas City | June 26, 2025 – July 31, 2025 | 35 | — |
| PBI→ORD West Palm Beach to Chicago | May 1–21, 2025 | 21 | — |
| ORD→ATL Chicago to Atlanta | August 19–23, 2024 | 3 | — |
| PIT→ORD Pittsburgh to Chicago | January 9, 2024 – June 26, 2024 | 146 | 69.7% |
| ORD→SNA Chicago to Santa Ana | February 15, 2024 – June 26, 2024 | 86 | — |
| SFO→RNO San Francisco to Reno | December 21, 2023 – January 8, 2024 | 19 | — |
| IAH→MSY Houston to New Orleans | September 29, 2023 – December 20, 2023 | 74 | — |
| PHL→IAH Philadelphia to Houston | November 28, 2023 – December 20, 2023 | 20 | — |
| ATL→IAH Atlanta to Houston | October 29, 2023 – November 27, 2023 | 27 | — |
| SAN→IAH San Diego to Houston | October 1–28, 2023 | 28 | — |
| LAX→IAH Los Angeles to Houston | July 1, 2023 – September 30, 2023 | 92 | 92.4% |
Because the same number has served different journeys, the statistics above describe only the route UA2040 currently operates. Blending them would produce an average of two different flights.
When it goes wrong
The average describes a usual day. This is the day that ruins a connection.
71 min late
against a median of 9 min late
UA2040 has an average that understates its risk: a typical arrival is 9 min late, but the worst tenth are 62 minutes worse than that. If the trip has something unmissable at the end of it, the median is the wrong number to plan against.
Percentiles over 738 operations; cancelled and diverted flights are counted separately.
Source: US DOT Bureau of Transportation Statistics · Data covering June 2024 – July 2026
Other flights on this route
Same airports, same journey, different odds of arriving on time.
| Flight | Airline | On time | Median arrival | Operations |
|---|---|---|---|---|
| UA1414 | United Airlines | 93.4% | 8 min early | 677 |
| AA1509 | American Airlines | 91.1% | 17 min early | 904 |
| UA1732 | United Airlines | 88.6% | 12 min early | 967 |
| B6311 | JetBlue | 85.2% | 10 min early | 974 |
| UA2040 this flight | United Airlines | 58.0% | 9 min late | 738 |
Every departure listed carries at least 600 operations, so the comparison is between figures that mean something. UA2040 is placed in the same ordering rather than left out of it; the rows around it are the most punctual departures on the route, not all of them, so this is a comparison and not a rank. Schedules change; confirm the departure still operates before booking around this.
Data and methodology
Calculated by FlyerIntel from 738 records of UA2040 operating BOS → ORD, published by the US DOT Bureau of Transportation Statistics. A flight counts as delayed when it arrives 15 or more minutes after schedule. Cancelled and diverted flights are excluded from the on-time rate and reported separately. Flight numbers are resolved as carrier plus number plus route, because the same number serves different routes over time.
Full methodology · Data sources · Report a problem
Related research: Most and Least Reliable Flight Numbers · The Delay You Inherit · Making Up Time in the Air
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