Flight number record
UA 251
United Airlines · Washington to New Orleans
- Route
- IAD → MSY
- Departs
- 17:50
- Flights
- 317
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 2026, not live status. For today’s UA 251, check with United Airlines.
UA 251 lands a B+, 5 points better than the national rate of 77.6%. About one flight in six arrives 15 minutes late or worse, and those flights are late by an hour and a half on average. That is a workable record, not a spotless one. That rests on 317 flights, with a median arrival 7 minutes early.
Set against the rest of the country, UA 251's record is 5 points better than the US average of 77.6%. That gap is worth roughly 47 fewer late arrivals for every thousand flights.
Key figures
On time
82.3%
Arrivals under 15 minutes late, of 316 completed flights
Avg delay
87 min
Across delayed arrivals only, not all flights
Cancelled
0.32%
National rate is 1.81%
1 hour+ late
8.2%
National rate is 8.1%
These figures cover 317 flights between July 2025 and June 2026. Beyond the headline rate, 8.2% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
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 317 flights, with 17:33 (79 flights) and 17:45 (72 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 17:5094 flights29.7%
- Departs 17:3379 flights24.9%
- Departs 17:4572 flights22.7%
Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.
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 68.2%, and UA 251 runs 14 points better at 82.3%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.
Against the route
UA 251 next to IAD to MSY
Every carrier on IAD to MSY combined arrived on time 85.6% of the time across 641 flights, so UA 251 is 3 points behind it. United flew 623 flights on the same city pair under all its flight numbers, including this one, and those ran 85.3% on time. Across its whole network United Airlines managed 79.0%, which this flight beats by 3 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 251thin sample | 317 | 82.3% | 87 min | 0.32% | B+ |
| All United Airlines on IAD–MSY | 623 | 85.3% | 80 min | 0.48% | A+ |
| All carriers on IAD–MSY | 641 | 85.6% | 80 min | 0.47% | A+ |
| United Airlines, whole network | 821,041 | 79.0% | 72 min | 1.01% | 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 Jul–Sep 2025 at 72.9%, a swing of 23 points on roughly 79 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 202585 flights72.9%
- Oct–Dec 202592 flights80.4%
- Jan–Mar 202690 flights85.4%
- Apr–Jun 202650 flights96.0%
Scale runs 65% to 100%. Rows with fewer than 30 flights show a dash.
By weekday, UA 251 did best on Monday at 93.5% on time and worst on Sunday at 68.9%. Each day rests on about 45 flights, so a gap of 25 points is worth noticing but could still narrow in another year.
Delay causes
Why UA 251 runs late
One category carries most of the weight here. Late-arriving aircraft accounts for 55% of the 4,871 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 55%Late-arriving aircraft
- 20%National Airspace System
- 18%Carrier
- 7%Extreme weather
55% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 4,871 reported delay minutes here, that single category outweighs weather by 7 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 4,871 delay minutes reported on UA 251.
Cancellations are rare at 0.32%, below the national 1.81% 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
8.2% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says 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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The same number turns up on six other city pairs in the data, including ABQ to IAH (41), IAH to TPA (30) and DEN to AVL (4), 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. 317 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 82.3% on time with 0.32% cancelled over 317 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.