Route reliability record
IAD→PIT
Washington to Pittsburgh
- Flights
- 1,213
- Period
- September 2025 to August 2026
- Distance
- 182 mi
- Carriers
- 2
This route 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 a little over an hour. That rests on 1,213 IAD to PIT flights, of which United Airlines flew 517 at 87.5% on time.
Best time to fly IAD to PIT: a 8am–11am departure, ideally on a Tuesday. Flights in that window arrived on time 91.8% of the time and Tuesday flights 86.8%, against 84.3% for the route overall.
Set against the rest of the country, this route's record is 7 points better than the US average of 77.3%. That gap is worth roughly 70 fewer late arrivals for every thousand flights.
Key figures
On time
84.3%
Arrivals under 15 minutes late, of 1,190 completed flights
Avg delay
76 min
Across delayed arrivals only, not all flights
Cancelled
1.73%
National rate is 1.89%
Best carrier
United
87.5% on time across 517 flights
These figures cover 1,213 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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Carrier by carrier
Which airline is most reliable on IAD to PIT
The two carriers here are closely matched: 6 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 517 | 87.5% | 79 min | 0.77% | A+ |
| Republic Airways | 696 | 81.9% | 74 min | 2.44% | B |
No carrier stands out. United tops the table at 87.5%, 6 points clear of the bottom, which is inside the range this kind of sample moves year to year.
Flight by flight
Flights on IAD to PIT
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.
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Best ways to make this trip
The most reliable ways to fly Washington to Pittsburgh
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. 3 of the top 5 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. IAD → PITWashington to Pittsburgh | United Airlines | 86.8% | 87.5% | 0.77% | 8am–11am, Wed | — |
| 2. IAD → PITWashington to Pittsburgh | Republic Airways | 79.9% | 81.9% | 2.44% | 11am–2pm, Mon | YX 3540 22:30 |
| 3. BWI → PITBaltimore to Pittsburgh | Southwest Airlines | 76.2% | 77.9% | 2.24% | 11am–2pm, Wed | — |
| 4. DCA → PITWashington to Pittsburgh | PSA Airlines | 70.0% | 75.1% | 6.74% | 5am–8am, Sat | — |
| 5. DCA → PITWashington to Pittsburgh | Republic Airways | 68.2% | 70.9% | 3.87% | 5am–8am, Sat | YX 4763 22:00 |
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 13 points, against 6 points between the best and worst carrier.
- 5am–8am—
- 8am–11am236 flights91.8%
- 11am–2pm284 flights90.4%
- 2pm–5pm—
- 5pm–8pm329 flights78.5%
- 8pm–5am364 flights79.8%
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 91.8% of the time, against 78.5% for the evening window. That is 13 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8pm–5am window is the busiest, with 364 flights scheduled in it.
Explore
Filter IAD to PIT 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 IAD to PIT, the best departure window is 8am–11am at 91.8% on time and the worst is 5pm–8pm at 78.5%, a wide gap of 13.3 points. All US flights leaving 8am–11am ran 83.9%.
- 5–8am—
- 8–11am91.8%
- 11am–2pm90.4%
- 2–5pm—
- 5–8pm78.5%
- 8pm–5am79.8%
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 21 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.
April is the best month on the calendar at 94.8% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. March was the busiest month here, with 115 flights.
Across the week, Tuesday is the strongest day at 86.8% on time and Sunday the weakest at 81.2%, a spread of 6 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 44% of the 14,000 delay minutes carriers reported here, and the remaining four split what is left.
- 44%Late-arriving aircraft
- 32%Carrier
- 21%National Airspace System
- 4%Extreme weather
44% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 14,000 reported delay minutes here, that single category outweighs weather by 11 to one. The split is drawn from 14,171 reported delay minutes.
The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 91.8% on time here.
Cancellations sit at 1.73% against a national 1.89%, which is ordinary. Diversions add another 0.16%.
Connections and stage length
What a delay here actually costs
5.7% 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 a little over an hour, which a normal layover absorbs.
At 182 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 8am–11am window matters as much as it does.
The return leg is a different operation and performs like one: it runs 87.9% on time across 1,210 flights, 4 points above this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 4 points of difference.
The sample behind these figures is 1,213 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
Work out the risk of missing a connection in PIT after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. April runs 94.8% on time and March 73.7%, a swing of 21 points. If the dates move at all, move them out of March before you think about anything else. 1,190 completed flights over 12 months sit behind that.
Common questions
IAD to PIT questions
How often is IAD to PIT delayed?
About one flight in six arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 15.7% of the 1,213 flights in this analysis, against 22.7% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on IAD to PIT?
United Airlines leads at 87.5% on time across 517 flights. Republic Airways is at the other end on 81.9%, a gap of 6 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on IAD to PIT?
The 8am–11am departure window is the strongest at 91.8% on time. The 5pm–8pm window is the weakest at 78.5%, 13 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 March delays on IAD to PIT?
March is the weakest month at 73.7% on time, compared with 94.8% in April. Across the year that is 21 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
- PIT to IAD — the return legseparate record
- Washington Dulles International (IAD) delay statistics
- Pittsburgh International (PIT) delay statistics
- United Airlines on IAD to PIT87.5%
- Republic Airways on IAD to PIT81.9%
- IAD to ATL, a related route78.0%
- ORD to PIT, a related route73.6%
- IAD to DEN, a related route83.1%
- United Airlines on-time record87.5%
- Republic Airways on-time record81.9%
- 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. IAD to PIT and PIT to IAD 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.