Carrier route record
UALAS→IAD
United Airlines · Las Vegas to Washington
- Flights
- 967
- Period
- September 2025 to August 2026
- Share of route
- 90%
- Carriers
- 2
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with United Airlines.
United on LAS to IAD earns an A+. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 11 points better than the national rate of 77.3%. When something does go wrong the average delay runs about an hour. That rests on 967 flights, with a median arrival 13 minutes early.
Set against the rest of the country, United's LAS to IAD record is 11 points better than the US average of 77.3%. That gap is worth roughly 109 fewer late arrivals for every thousand flights.
Key figures
On time
88.2%
Arrivals under 15 minutes late, of 950 completed flights
Avg delay
63 min
Across delayed arrivals only, not all flights
Cancelled
0.62%
National rate is 1.89%
Whole route
85.5%
Every carrier on LAS to IAD, 1,070 flights
These figures cover 967 flights between September 2025 and August 2026. The median arrival is 13 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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Carrier by carrier
United against every carrier on LAS to IAD
United flew 967 of the 1,070 flights on LAS to IAD, most of the route. Its 88.2% on time is 3 points better than the route as a whole, which runs 85.5%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from United at 88.2% to Frontier at 59.8%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines (this page) | 967 | 88.2% | 63 min | 0.62% | A+ |
| Frontier Airlinesthin sample | 103 | 59.8% | 52 min | 0.97% | D+ |
Flight by flight
United flight numbers on LAS to IAD
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Departure window
When United runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 13 points, against half a point between the best and worst carrier.
- 5am–8am—
- 8am–11am361 flights91.9%
- 11am–2pm266 flights81.1%
- 2pm–5pm99 flights80.4%
- 5pm–8pm—
- 8pm–5am241 flights93.7%
Scale runs 70% to 100%. Rows with fewer than 30 flights show a dash.
The overnight block holds up unusually well at 93.7% on time across 241 flights. Red-eyes fly into empty airspace and empty gates, and they are the first rotation of the aircraft's day rather than the last. The 8am–11am window is the busiest, with 361 flights scheduled in it.
Across the year
United on LAS to IAD through the year
July is the worst month at 69.0% on time, 26 points below October, the best at 94.6%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. October was the busiest month here, with 93 flights.
Across the week, Tuesday is the strongest day at 91.0% on time and Sunday the weakest at 82.5%, a spread of 9 points.
Arrival by arrival
How late United on LAS to IAD runs when it is late
United on LAS to IAD often beats the schedule: 449 of 950 completed flights, 47%, arrived 15 minutes or more early. The 112 late arrivals split 51 under half an hour, 28 between 30 and 60 minutes, and 33 an hour or more.
- 15+ min early449 flights47.3%
- Within 15 min389 flights40.9%
- 15–29 min late51 flights5.4%
- 30–59 min late28 flights2.9%
- 1–2 hours late11 flights1.2%
- 2+ hours late22 flights2.3%
Scale runs 0% to 100%.
Share of 950 completed flights by arrival against schedule.
32 of 112 late departures made up the time and arrived on time, 29% of them. 32 flights left on time and still arrived late.
The worst days
Worst days for United on LAS to IAD
The latest arrival of the period was on 9 August 2026, 7 hours 59 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 |
|---|---|---|
| 9 August 2026 | 7 hours 59 minutes | Late-arriving aircraft |
| 27 November 2025 | 4 hours 41 minutes | Carrier |
| 16 March 2026 | 3 hours 32 minutes | Late-arriving aircraft |
| 18 July 2026 | 3 hours 28 minutes | National Airspace System |
| 10 August 2026 | 3 hours 27 minutes | Late-arriving aircraft |
Delay causes
Why United runs late on this route
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 7,038 reported delay minutes.
- 39%Carrier
- 38%Late-arriving aircraft
- 22%National Airspace System
- 0%Extreme weather
38% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 7,038 reported delay minutes here, that single category outweighs weather by 38 to one. The split is drawn from 7,038 reported delay minutes.
The largest share of delay minutes, 39%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 2,768 of the 7,038 delay minutes reported here.
Cancellations are rare at 0.62%, 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 stage length
What a delay here costs
Badly late arrivals are rare here: only 3.5% land an hour or more behind schedule, against 8.3% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
At 2,065 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The return leg runs 88.0% on time across 965 flights, within half a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
One caution: this is a thin sample. 967 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 United on LAS to IAD
Put together: treat all of this as provisional. 967 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 88.2% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 950 completed flights over 12 months sit behind that.
Related
Where to go next
- LAS to IAD, every carrier
- United on IAD to LAS, the return leg
- Frontier Airlines on LAS to IAD59.8%
- United Airlines network-wide record
- Harry Reid International (LAS) delay statistics
- Washington Dulles International (IAD) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
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.