Flight profile · United Airlines
UA1524
Washington (IAD) to Houston (IAH) · scheduled 8:30 AM – 11:00 AM
How UA1524 performs
606 operations, September 2024 – July 2026.
UA1524 arrived on time 87.2% of the time, against 81.0% for all IAD → IAH flights, so this departure is 6.2 percentage points better than the route as a whole. Against United Airlines’ own flights on this route it is 6.2 points better.
Source: US DOT Bureau of Transportation Statistics · 606 operations, September 2024 – July 2026 · If UA1524 is cancelled or significantly changed, DOT’s automatic refund rule may entitle you to your money back. The refund checker walks through eligibility.
Where UA1524 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 |
|---|---|---|---|---|---|
| UA1524 | 87.2% | 0.83% | -10 min | 3.7% | 606 |
| United Airlines on IAD → IAH | 81.0% | 0.82% | -7 min | 6.0% | 5,508 |
| All IAD → IAH flights | 81.0% | 0.82% | -7 min | 6.0% | 5,508 |
Source: FlyerIntel analysis of US DOT BTS data · September 2024 – July 2026
Why UA1524 runs late
Where US DOT attributed the delay minutes on this flight.
airspace and airport capacity, including weather-driven flow control
crew, maintenance, boarding and fueling, all within the carrier’s control
the inbound aircraft was late, so this flight started late
weather severe enough to stop this flight specifically
Share of the delay minutes US DOT attributed to each cause for UA1524 on IAD → IAH. Only delays of 15 minutes or more are attributed.
Source: US DOT Bureau of Transportation Statistics · Data covering September 2024 – July 2026
Does a late aircraft delay this flight?
How often the plane that flies UA1524 comes in late, and what that does to the departure.
UA1524 is usually the aircraft’s first flight of the day: the schedule gives it a median of 8 hours on the ground at IAD, so its “inbound” is mostly the aircraft’s arrival the evening before.
The aircraft flying UA1524 came in 15 or more minutes late on 17% of the departures where its previous flight is known. There are not enough departures in both groups to say how the flight left after a late one and after an on-time one.
Each departure is matched to the flight the same aircraft flew into IAD just before it, using the tail number in the DOT file, 494 of 601 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 |
|---|---|
| UA1524 | 17% |
| Network, same turn | 29% |
A night on the ground absorbs most of a late arrival, so a late inbound matters far less on a turn this long than on a same-day one.
The network row is every flight with a scheduled turn of 6 hours or more, usually overnight. How often UA1524’s aircraft landed 15 or more minutes late is lower than the network’s. There are not enough departures in both groups to compare how it left.
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 September 2024 – July 2026
From pushback to gate
When it leaves IAD late, does that still matter by the time it reaches IAH?
UA1524 pushes back an average of 5.6 minutes late and reaches the gate at IAH an average of 2.2 minutes early. The 7.8 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. It spends 23.4 minutes on the taxiways at IAD, 2.4 minutes longer than a typical IAD departure in the same hour.
On arrival at IAH, UA1524 spends 9.5 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 1.1 minutes shorter than a typical IAH arrival (10.7 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 IAH. Taxi-out is gate to wheels up and sits inside the scheduled block rather than on top of it; the comparison is 32,899 departures from IAD scheduled in the clock hour UA1524 most often leaves in. Taxi-in is landing to gate, compared against every arrival FlyerIntel has on file at IAH (359,471 flights), not just UA1524’s own. More on taxi time.
Source: FlyerIntel analysis of US DOT BTS data · September 2024 – July 2026
The hour it leaves IAD
Part of any flight’s record belongs to the clock rather than to the flight. UA1524 has one departure time, so this is what that time is worth.
On-time arrival rate. 32,899 departures from IAD are scheduled in the 8 AM–9 AM hour over the period, against 170,208 across the whole day.
UA1524 is scheduled out of IAD at 8:30 AM, in the 8 AM–9 AM bank. Departures from IAD in that hour arrive on time 88.0% of the time against 81.0% across the airport’s whole day — the slot alone is worth 7.1 points better before anything about this particular flight is considered.
The two airport figures cover every departure from IAD 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 · September 2024 – July 2026 · Hours below 120 departures are not scored.
Other routes UA1524 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 |
|---|---|---|---|
| IAH→LAS Houston to Las Vegas | September 25, 2025 – July 31, 2026 | 220 | 88.2% |
| ORF→IAD Norfolk to Washington | December 19, 2025 – July 31, 2026 | 111 | 93.7% |
| CHS→IAD Charleston to Washington | April 1–29, 2026 | 13 | — |
| IAH→SAT Houston to San Antonio | June 27, 2024 – December 2, 2024 | 108 | 72.9% |
| CLT→ORD Charlotte to Chicago | November 30, 2024 – December 1, 2024 | 2 | — |
| ORD→LAX Chicago to Los Angeles | November 30, 2024 – December 1, 2024 | 2 | — |
| ANC→ORD Anchorage to Chicago | November 24, 2024 | 1 | — |
| DFW→IAH Dallas–Fort Worth to Houston | November 28, 2023 – June 26, 2024 | 116 | 81.6% |
| RSW→ORD Fort Myers to Chicago | January 9, 2024 – May 22, 2024 | 54 | — |
| IAH→PHL Houston to Philadelphia | March 7–30, 2024 | 24 | — |
| DEN→FCA Denver to Kalispell | January 14, 2024 | 1 | — |
| IAH→MSY Houston to New Orleans | December 22, 2023 – January 8, 2024 | 15 | — |
| DSM→IAH Des Moines to Houston | December 21, 2023 | 1 | — |
| ORD→BOS Chicago to Boston | December 3–17, 2023 | 3 | — |
| IAH→CHS Houston to Charleston | July 1, 2023 – November 27, 2023 | 138 | 81.2% |
| AUS→EWR Austin to Newark | October 20–23, 2023 | 2 | — |
| MAF→IAH Midland to Houston | October 13–15, 2023 | 2 | — |
| EWR→IAD Newark to Washington | September 30, 2023 | 1 | — |
Because the same number has served different journeys, the statistics above describe only the route UA1524 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.
20 min late
against a median of 10 min early
Percentiles over 606 operations; cancelled and diverted flights are counted separately.
Source: US DOT Bureau of Transportation Statistics · Data covering September 2024 – July 2026
Data and methodology
Calculated by FlyerIntel from 606 records of UA1524 operating IAD → IAH, 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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