Flight profile · United Airlines
UA1938
Washington (IAD) to Phoenix (PHX) · scheduled 5:50 PM – 7:15 PM
How UA1938 performs
983 operations, July 2023 – July 2026.
UA1938 arrived on time 77.5% of the time, against 81.5% for all IAD → PHX flights, so this departure is 4.0 percentage points worse than the route as a whole. Against United Airlines’ own flights on this route it is 7.4 points worse.
Source: US DOT Bureau of Transportation Statistics · 983 operations, July 2023 – July 2026 · If UA1938 is cancelled or significantly changed, DOT’s automatic refund rule may entitle you to your money back. The refund checker walks through eligibility.
Where UA1938 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 |
|---|---|---|---|---|---|
| UA1938 | 77.5% | 1.83% | -6 min | 8.4% | 983 |
| United Airlines on IAD → PHX | 84.9% | 1.11% | -11 min | 5.4% | 2,334 |
| All IAD → PHX flights | 81.5% | 0.97% | -8 min | 5.8% | 3,101 |
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026
Why UA1938 runs late
Where US DOT attributed the delay minutes on this flight.
the inbound aircraft was late, so this flight started late
airspace and airport capacity, including weather-driven flow control
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 UA1938 on IAD → PHX. 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 UA1938 comes in late, and what that does to the departure.
The aircraft flying UA1938 came in 15 or more minutes late on 16% 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, 732 of 965 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 |
|---|---|
| UA1938 | 16% |
| Network, same turn | 17% |
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 60 to 89 minutes. How often UA1938’s aircraft landed 15 or more minutes late is about the same as 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 July 2023 – July 2026
From pushback to gate
When it leaves IAD late, does that still matter by the time it reaches PHX?
UA1938 pushes back an average of 15.9 minutes late and reaches the gate at PHX an average of 7.0 minutes late. The 8.9 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 24.2 minutes on the taxiways at IAD is about what any departure from the airport in that hour spends.
On arrival at PHX, UA1938 spends 5.0 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 2.5 minutes shorter than a typical PHX arrival (7.5 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 PHX. Taxi-out is gate to wheels up and sits inside the scheduled block rather than on top of it; the comparison is 37,767 departures from IAD scheduled in the clock hour UA1938 most often leaves in. Taxi-in is landing to gate, compared against every arrival FlyerIntel has on file at PHX (598,496 flights), not just UA1938’s own. More on taxi time.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026
The hour it leaves IAD
Part of any flight’s record belongs to the clock rather than to the flight. UA1938 has one departure time, so this is what that time is worth.
On-time arrival rate. 37,767 departures from IAD are scheduled in the 5 PM–6 PM hour over the period, against 170,208 across the whole day.
UA1938 is scheduled out of IAD at 5:50 PM, in the 5 PM–6 PM bank. Departures from IAD in that hour arrive on time 72.1% of the time against 81.0% across the airport’s whole day — the slot alone is worth 8.9 points worse 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 · July 2023 – July 2026 · Hours below 120 departures are not scored.
By day of week
Does UA1938 run worse on particular days?
Tuesday is historically the most reliable day and Saturday the least, a gap of 9.1 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 UA1938 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 |
|---|---|---|---|
| JAX→IAD Jacksonville to Washington | January 7, 2025 – May 20, 2026 | 375 | 88.7% |
| ORD→JAX Chicago to Jacksonville | February 12, 2026 – April 29, 2026 | 44 | — |
| PHX→ORD Phoenix to Chicago | November 29–30, 2025 | 2 | — |
| EWR→JAX Newark to Jacksonville | June 16–25, 2025 | 9 | — |
| IAD→LAS Washington to Las Vegas | January 6, 2025 | 1 | — |
| MIA→IAD Miami to Washington | September 29, 2023 – August 18, 2024 | 172 | 81.7% |
Because the same number has served different journeys, the statistics above describe only the route UA1938 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.
46 min late
against a median of 6 min early
Percentiles over 983 operations; cancelled and diverted flights are counted separately.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
Data and methodology
Calculated by FlyerIntel from 983 records of UA1938 operating IAD → PHX, 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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