Flight profile · United Airlines
UA1240
Dallas–Fort Worth (DFW) to Washington (IAD) · scheduled 5:25 PM – 9:25 PM
How UA1240 performs
952 operations, July 2023 – July 2026.
Source: US DOT Bureau of Transportation Statistics · 952 operations, July 2023 – July 2026 · If UA1240 is cancelled or significantly changed, DOT’s automatic refund rule may entitle you to your money back. The refund checker walks through eligibility.
Where UA1240 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 |
|---|---|---|---|---|---|
| UA1240 | 76.5% | 1.37% | -4 min | 11.0% | 952 |
| United Airlines on DFW → IAD | 82.5% | 1.25% | -6 min | 7.2% | 2,968 |
| All DFW → IAD flights | 77.0% | 1.74% | -4 min | 8.9% | 5,639 |
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026
Why UA1240 runs late
Where US DOT attributed the delay minutes on this flight.
the inbound aircraft was late, so this flight started late
crew, maintenance, boarding and fueling, all within the carrier’s control
airspace and airport capacity, including weather-driven flow control
weather severe enough to stop this flight specifically
Share of the delay minutes US DOT attributed to each cause for UA1240 on DFW → IAD. Only delays of 15 minutes or more are attributed.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
Does a late aircraft delay this flight?
How often the plane that flies UA1240 comes in late, and what that does to the departure.
When the aircraft came in 15 or more minutes late, UA1240 pushed back an average of 53 minutes late; when it came in on time or early, an average of 3 minutes late.
Each departure is matched to the flight the same aircraft flew into DFW just before it, using the tail number in the DOT file, 913 of 940 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 |
|---|---|---|---|
| UA1240 | 20% | 77% | 9% |
| Network, same turn | 18% | 85% | 10% |
The schedule leaves a normal turn: enough time to clean and board if the aircraft is on time, little to spare if it is not.
The network row is every flight with a scheduled turn of 45 to 59 minutes. How often UA1240’s aircraft landed 15 or more minutes late is about the same as the network’s and, once the aircraft was late, how often UA1240 left 15 or more minutes late is lower 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 July 2023 – July 2026
From pushback to gate
When it leaves DFW late, does that still matter by the time it reaches IAD?
UA1240 pushes back an average of 16.5 minutes late and reaches the gate at IAD an average of 12.3 minutes late. The 4.2 minutes between those two figures are slack the published schedule already carries, which is why a late pushback on this flight does not reliably become a late arrival. Its 19.4 minutes on the taxiways at DFW is about what any departure from the airport in that hour spends.
On arrival at IAD, UA1240 spends 7.5 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 about what any arrival at IAD spends on the ground before reaching the gate.
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 IAD. Taxi-out is gate to wheels up and sits inside the scheduled block rather than on top of it; the comparison is 52,089 departures from DFW scheduled in the clock hour UA1240 most often leaves in. Taxi-in is landing to gate, compared against every arrival FlyerIntel has on file at IAD (169,930 flights), not just UA1240’s own. More on taxi time.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026
The hour it leaves DFW
Part of any flight’s record belongs to the clock rather than to the flight. UA1240 has one departure time, so this is what that time is worth.
On-time arrival rate. 52,089 departures from DFW are scheduled in the 5 PM–6 PM hour over the period, against 961,718 across the whole day.
UA1240 is scheduled out of DFW at 5:25 PM, in the 5 PM–6 PM bank. Departures from DFW in that hour arrive on time 65.7% of the time against 73.1% across the airport’s whole day — the slot alone is worth 7.4 points worse before anything about this particular flight is considered.
The two airport figures cover every departure from DFW 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 · July 2023 – July 2026 · Hours below 120 departures are not scored.
By day of week
Does UA1240 run worse on particular days?
Tuesday is historically the most reliable day and Sunday the least, a gap of 11.5 percentage points.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · Days with fewer than 120 operations are not scored.
Other routes UA1240 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 |
|---|---|---|---|
| SFO→EWR San Francisco to Newark | February 9, 2026 | 1 | — |
| ORD→FCA Chicago to Kalispell | December 18, 2025 – January 5, 2026 | 19 | — |
| MSY→EWR New Orleans to Newark | December 19, 2024 – January 6, 2025 | 19 | — |
| SFO→DFW San Francisco to Dallas–Fort Worth | July 1, 2023 – October 25, 2024 | 282 | 78.2% |
| IAD→IAH Washington to Houston | May 22, 2024 | 1 | — |
| DEN→FLL Denver to Fort Lauderdale | March 31, 2024 – May 19, 2024 | 6 | — |
| ORD→FAT Chicago to Fresno | May 1, 2024 | 1 | — |
| ATL→DEN Atlanta to Denver | April 10–14, 2024 | 2 | — |
| SEA→SFO Seattle to San Francisco | September 5, 2023 – February 14, 2024 | 160 | 72.3% |
| IAH→IAD Houston to Washington | July 3, 2023 | 1 | — |
Because the same number has served different journeys, the statistics above describe only the route UA1240 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.
64 min late
against a median of 4 min early
UA1240 has an average that understates its risk: a typical arrival is 4 min early, but the worst tenth are 68 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 952 operations; cancelled and diverted flights are counted separately.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
Other flights on this route
Same airports, same journey, different odds of arriving on time.
| Flight | Airline | On time | Median arrival | Operations |
|---|---|---|---|---|
| UA2639 | United Airlines | 89.0% | 8 min early | 987 |
| UA358 | United Airlines | 83.3% | 6 min early | 937 |
| UA1240 this flight | United Airlines | 76.5% | 4 min early | 952 |
Every departure listed carries at least 600 operations, so the comparison is between figures that mean something. UA1240 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 952 records of UA1240 operating DFW → IAD, 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
Analysis last recomputed