Route reliability record
LAS→IAD
Las Vegas to Washington
- Flights
- 1,070
- Period
- September 2025 to August 2026
- Distance
- 2,065 mi
- Carriers
- 2
This route earns an A+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 8 points better than the national rate of 77.3%. When something does go wrong the average delay runs about an hour. That rests on 1,070 LAS to IAD flights, with a median arrival 11 minutes early.
Best time to fly LAS to IAD: a 8am–11am departure, ideally on a Wednesday. Flights in that window arrived on time 91.9% of the time and Wednesday flights 87.2%, against 85.5% for the route overall.
Set against the rest of the country, this route's record is 8 points better than the US average of 77.3%. That gap is worth roughly 82 fewer late arrivals for every thousand flights.
Key figures
On time
85.5%
Arrivals under 15 minutes late, of 1,052 completed flights
Avg delay
60 min
Across delayed arrivals only, not all flights
Cancelled
0.65%
National rate is 1.89%
Best carrier
United
88.2% on time across 967 flights
These figures cover 1,070 flights between September 2025 and August 2026. The median arrival is 11 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
Which airline is most reliable on LAS to IAD
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 | 967 | 88.2% | 63 min | 0.62% | A+ |
| Frontier Airlinesthin sample | 103 | 59.8% | 52 min | 0.97% | D+ |
Flight by flight
Flights on LAS to IAD
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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.
Best ways to make this trip
The most reliable ways to fly Las Vegas to Washington
Every airline on this route and on the routes between nearby airports, ranked by how often a scheduled flight actually operated and arrived on time. 1 of the top 2 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. LAS → IADLas Vegas to Washington | United Airlines | 87.7% | 88.2% | 0.62% | 8pm–5am, Tue | UA 2382 13:23 |
| 2. LAS → BWILas Vegas to Baltimore | Southwest Airlines | 77.7% | 78.6% | 1.10% | 5am–8am, Sat | — |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 12 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–5am344 flights83.5%
Scale runs 70% to 95%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 91.9% of the time, against 80.4% for the afternoon window. That is 12 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 361 flights scheduled in it.
Explore
Filter LAS to IAD by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On LAS to IAD, the best departure window is 8am–11am at 91.9% on time and the worst is 2pm–5pm at 80.4%, a wide gap of 11.5 points. All US flights leaving 8am–11am ran 83.9%.
- 5–8am—
- 8–11am91.9%
- 11am–2pm81.1%
- 2–5pm80.4%
- 5–8pm—
- 8pm–5am83.5%
best all US flightsScale 60% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 31 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
July is the worst month at 64.0% on time, 31 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. August was the busiest month here, with 111 flights.
Across the week, Wednesday is the strongest day at 87.2% on time and Sunday the weakest at 80.9%, a spread of 6 points.
Delay causes
Why this route gets delayed
Carrier accounts for 42% of the 9,158 delay minutes carriers reported here, and the remaining four split what is left.
- 42%Carrier
- 38%Late-arriving aircraft
- 20%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 9,158 reported delay minutes here, that single category outweighs weather by 38 to one. The split is drawn from 9,158 reported delay minutes.
The largest share of delay minutes, 42%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 3,857 of the 9,158 delay minutes reported here.
Cancellations are rare at 0.65%, 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 actually costs
Badly late arrivals are rare here: only 4.1% 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 85.3% on time across 1,069 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. 1,070 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.
Work out the risk of missing a connection in IAD after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 1,070 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 85.5% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 1,052 completed flights over 12 months sit behind that.
Common questions
LAS to IAD questions
How often is LAS to IAD delayed?
About one flight in seven arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 14.5% of the 1,070 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
How reliable is LAS to IAD compared with the rest of the country?
85.5% of flights arrive on time here against a national 77.3%, a difference of 8 points in its favour. That is worth a A+ on this site's grading scale.
What time of day has the fewest delays on LAS to IAD?
The 8am–11am departure window is the strongest at 91.9% on time. The 2pm–5pm window is the weakest at 80.4%, 12 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are July delays on LAS to IAD?
July is the weakest month at 64.0% on time, compared with 94.6% in October. Across the year that is 31 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- IAD to LAS — the return legseparate record
- Harry Reid International (LAS) delay statistics
- Washington Dulles International (IAD) delay statistics
- United Airlines on LAS to IAD88.2%
- Frontier Airlines on LAS to IAD59.8%
- LAS to LAX, a related route77.9%
- ATL to IAD, a related route76.4%
- LAS to DEN, a related route76.5%
- United Airlines on-time record88.2%
- Frontier Airlines on-time record59.8%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
Direction matters. LAS to IAD and IAD to LAS are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.