Route reliability record
ORD→PIT
Chicago to Pittsburgh
- Flights
- 3,948
- Period
- July 2025 to June 2026
- Distance
- 413 mi
- Carriers
- 5
This route sits in the middle of the pack with a C. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 3,948 flights, of which Republic Airways flew 1,628 at 81.4% on time.
Republic Airways is the most reliable of the three carriers covered here at 81.4% on time across 1,628 flights.
Key figures
On time
74.9%
Arrivals under 15 minutes late, of 3,867 completed flights
Avg delay
81 min
Across delayed arrivals only, not all flights
Cancelled
1.95%
National rate is 1.81%
Best carrier
Republic
81.4% on time across 1,628 flights
These figures cover 3,948 flights between July 2025 and June 2026. Beyond the headline rate, 10.2% 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.
Carrier by carrier
Which airline is most reliable on ORD to PIT
The choice of carrier is not cosmetic here. Republic Airways arrives on time 81.4% of the time; American Airlines manages 55.0%. Sample sizes sit next to every figure, because a two-point gap across 603 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Envoy Airthin sample | 189 | 83.2% | 64 min | 2.12% | B |
| Republic Airways | 1,628 | 81.4% | 80 min | 2.27% | B |
| United Airlines | 1,291 | 75.8% | 66 min | 1.01% | B |
| SkyWest Airlinesthin sample | 237 | 68.5% | 66 min | 2.11% | C |
| American Airlines | 603 | 55.0% | 105 min | 2.99% | D |
The spread between Republic and American is 26 points, wide enough that it should decide the booking. On a hundred trips that is 26 more arrivals inside the on-time window.
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 21 points, against 26 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am370 flights86.4%
- 8am–11am789 flights81.3%
- 11am–2pm419 flights83.1%
- 2pm–5pm888 flights71.2%
- 5pm–8pm868 flights65.4%
- 8pm–5am614 flights72.4%
Scale runs 55% to 90%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 86.4% of the time, against 65.4% for the evening window. That is 21 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 2pm–5pm window is the busiest, with 888 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 25 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.
September is the best month on the calendar at 85.2% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. May was the busiest month here, with 397 flights.
Across the week, Tuesday is the strongest day at 81.9% on time and Monday the weakest at 68.9%. 13 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. Late-arriving aircraft accounts for 52% of the 78,000 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.
- 52%Late-arriving aircraft
- 26%Carrier
- 14%National Airspace System
- 8%Extreme weather
52% 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 78,000 reported delay minutes here, that single category outweighs weather by 6 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 78,395 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 86.4% on time here.
Cancellations sit at 1.95% against a national 1.81%, which is ordinary. Diversions add another 0.10%.
Connections and stage length
What a delay here actually costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 10.2% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.
At 413 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 5am–8am window matters as much as it does.
The return leg is a different operation and performs like one: it runs 78.6% on time across 3,950 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 3,948 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.
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 85.2% on time and March 60.1%, a swing of 25 points. If the dates move at all, move them out of March before you think about anything else. 3,867 completed flights over 12 months sit behind that.
Common questions
ORD to PIT questions
How often is ORD to PIT delayed?
About one flight in four arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 25.1% of the 3,948 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on ORD to PIT?
Republic Airways leads at 81.4% on time across 1,628 flights. American Airlines is at the other end on 55.0%, a gap of 26 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 ORD to PIT?
The 5am–8am departure window is the strongest at 86.4% on time. The 5pm–8pm window is the weakest at 65.4%, 21 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 ORD to PIT?
March is the weakest month at 60.1% on time, compared with 85.2% in September. Across the year that is 25 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 ORD — the return legseparate record
- Chicago O'Hare International (ORD) delay statistics
- Pittsburgh International (PIT) delay statistics
- Envoy Air on-time record83.2%
- Republic Airways on-time record81.4%
- United Airlines on-time record75.8%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. ORD to PIT and PIT to ORD are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.