Flight number record
UA 251
United Airlines · Washington to New Orleans
- Route
- IAD → MSY
- Departs
- 17:50
- Flights
- 283
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s UA 251, check with United Airlines.
UA 251 earns a B+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 7 points better than the national rate of 77.3%. When something does go wrong the average delay runs an hour and a half. That rests on 283 flights, with a median arrival 8 minutes early.
Set against the rest of the country, UA 251's record is 7 points better than the US average of 77.3%. That gap is worth roughly 67 fewer late arrivals for every thousand flights.
Key figures
On time
84.0%
Arrivals under 15 minutes late, of 282 completed flights
Avg delay
84 min
Across delayed arrivals only, not all flights
Cancelled
0.35%
National rate is 1.89%
1 hour+ late
7.4%
National rate is 8.3%
These figures cover 283 flights between September 2025 and August 2026. The median arrival is 8 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
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Schedule
When UA 251 flies
UA 251 flies IAD to MSY without a single fixed slot. Its most common scheduled departure was 17:50, used on 94 of 283 flights, with 17:45 (72 flights) and 17:42 (37 flights) next.
- Departs 17:5094 flights33.2%
- Departs 17:4572 flights25.4%
- Departs 17:4237 flights13.1%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 17:50 departure sits in the 5pm–8pm window. Across every US flight scheduled in that window the on-time rate is 68.0%, and UA 251 runs 16 points better at 84.0%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.
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Against the route
UA 251 next to IAD to MSY
Every carrier on IAD to MSY combined arrived on time 84.8% of the time across 622 flights, so UA 251 is about level with it. United flew 608 flights on the same city pair under all its flight numbers, including this one, and those ran 84.6% on time. Across its whole network United Airlines managed 78.8%, which this flight beats by 5 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 251thin sample | 283 | 84.0% | 84 min | 0.35% | B+ |
| All United Airlines on IAD–MSY | 608 | 84.6% | 82 min | 0.49% | B+ |
| All carriers on IAD–MSY | 622 | 84.8% | 81 min | 0.48% | B+ |
| United Airlines, whole network | 830,825 | 78.8% | 73 min | 1.02% | B |
Across the year
UA 251 quarter by quarter
UA 251 did not run the same all year. Its best quarter was Apr–Jun 2026 at 96.0% on time and its weakest Oct–Dec 2025 at 80.4%, a swing of 16 points on roughly 71 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 202530 flights93.3%
- Oct–Dec 202592 flights80.4%
- Jan–Mar 202690 flights85.4%
- Apr–Jun 202650 flights96.0%
- Jul–Sep 202621 flights—
Scale runs 70% to 100%. Rows with fewer than 30 flights show a dash.
By weekday, UA 251 did best on Tuesday at 95.1% on time and worst on Sunday at 74.4%. Each day rests on about 40 flights, so a gap of 21 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late UA 251 runs when it is late
UA 251 often beats the schedule: 94 of 282 completed flights, 33%, arrived 15 minutes or more early. The 45 late arrivals split 10 under half an hour, 14 between 30 and 60 minutes, and 21 an hour or more.
- 15+ min early94 flights33.3%
- Within 15 min143 flights50.7%
- 15–29 min late10 flights3.5%
- 30–59 min late14 flights5.0%
- 1–2 hours late10 flights3.5%
- 2+ hours late11 flights3.9%
Scale runs 0% to 100%.
Share of 282 completed flights by arrival against schedule.
A late pushback is often recovered here: of 44 departures that left 15 minutes late or more, 14 still arrived on time. In the other direction, 15 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at MSY.
The worst days
Worst days for UA 251
The latest arrival of the period was on 14 December 2025, 4 hours 41 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 14 December 2025 | 4 hours 41 minutes | Late-arriving aircraft |
| 16 August 2026 | 4 hours 15 minutes | Carrier |
| 19 February 2026 | 3 hours 39 minutes | Late-arriving aircraft |
| 29 November 2025 | 3 hours 35 minutes | Late-arriving aircraft |
| 9 November 2025 | 3 hours 13 minutes | Carrier |
Delay causes
Why UA 251 runs late
Late-arriving aircraft accounts for 44% of the 3,796 delay minutes carriers reported here, and the remaining four split what is left.
- 44%Late-arriving aircraft
- 26%National Airspace System
- 25%Carrier
- 5%Extreme weather
44% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 3,796 reported delay minutes here, that single category outweighs weather by 9 to one. The split is drawn from 3,796 delay minutes reported on UA 251.
Cancellations are rare at 0.35%, below the national 1.89% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and routes
What a delay on this flight costs
7.4% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last an hour and a half, which a normal layover absorbs.
The 955 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.
The same number turns up on three other city pairs in the data, including ABQ to IAH (82), IAH to TPA (30) and MSY to SFO (3), but none flew often enough under UA 251 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to IAD to MSY only.
One caution: this is a thin sample. 283 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 251
For a booking, read UA 251 as 84.0% on time with 0.35% cancelled over 283 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- Washington Dulles International (IAD) delay statistics
- Louis Armstrong New Orleans International (MSY) 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
- Why the first flight of the morning is statistically safest
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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.