Route reliability record

PIT→ORD

Pittsburgh to Chicago

Flights: 3,950
Period: July 2025 to June 2026
Distance: 413 mi
Carriers: 5

This route lands a B, about a point better than the national rate of 77.6%. About one flight in five arrive 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 3,950 flights, of which Republic Airways flew 1,629 at 84.2% on time.

Republic Airways is the most reliable of the three carriers covered here at 84.2% on time across 1,629 flights.

On time

78.6%

Arrivals under 15 minutes late, of 3,865 completed flights

Avg delay

94 min

Across delayed arrivals only, not all flights

Cancelled

2.00%

National rate is 1.81%

Best carrier

Republic

84.2% on time across 1,629 flights

These figures cover 3,950 flights between July 2025 and June 2026. Beyond the headline rate, 9.3% 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 PIT to ORD

The choice of carrier is not cosmetic here. Republic Airways arrives on time 84.2% of the time; American Airlines manages 69.9%. Sample sizes sit next to every figure, because a two-point gap across 604 flights means less than a ten-point one.

On-time performance by carrier on PIT to ORD
Airline	Flights	On time	Avg delay	Cancelled	Grade
Republic Airways	1,629	84.2%	74 min	1.66%	B
Envoy Airthin sample	190	78.3%	105 min	2.63%	B
United Airlines	1,290	77.9%	95 min	1.86%	B
American Airlines	604	69.9%	113 min	2.98%	C
SkyWest Airlinesthin sample	237	65.1%	105 min	2.11%	C

The spread between Republic and American is 14 points, wide enough that it should decide the booking. On a hundred trips that is 14 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 41 points, against 14 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am767 flights89.9%
8am–11am967 flights85.8%
11am–2pm521 flights84.9%
2pm–5pm826 flights76.6%
5pm–8pm749 flights59.7%
8pm–5am120 flights48.7%

Scale runs 40% to 95%. Rows with fewer than 30 flights show a dash.

The 8pm–5am window is where this operation falls apart: 48.7% on time, against 89.9% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 8am–11am window is the busiest, with 967 flights scheduled in it.

Across the year

When delays peak on this route

This route's year swings by 17 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.

Darker means more delays. Figures are on-time percentages.February best, December worst

December is the weak month at 68.9% on time, against 85.5% in February. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. May was the busiest month here, with 396 flights.

Across the week, Saturday is the strongest day at 82.7% on time and Monday the weakest at 74.3%. 8 points is a smaller lever than departure hour, but it is free.

Delay causes

Why this route gets delayed

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 78,000 reported delay minutes.

National Airspace System
41%
Late-arriving aircraft
31%
Carrier
22%
Extreme weather
5%
Security
0%

41% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 32,000 minutes out of 78,000, against a national NAS share of 21%. The split is drawn from 77,710 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 89.9% on time here.

Cancellations sit at 2.00% against a national 1.81%, which is ordinary. Diversions add another 0.15%.

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. 9.3% 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 74.9% on time across 3,948 flights, 4 points below 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 3,950 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. February runs 85.5% on time and December 68.9%, a swing of 17 points. If the dates move at all, move them out of December before you think about anything else. 3,865 completed flights over 12 months sit behind that.

Common questions

PIT to ORD questions

How often is PIT to ORD delayed?

About one flight in five arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 21.4% of the 3,950 flights in this analysis, against 22.4% nationally. Delayed flights are late by an hour and a half on average.

Which airline is most reliable on PIT to ORD?

Republic Airways leads at 84.2% on time across 1,629 flights. American Airlines is at the other end on 69.9%, a gap of 14 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 PIT to ORD?

The 5am–8am departure window is the strongest at 89.9% on time. The 8pm–5am window is the weakest at 48.7%, 41 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 December delays on PIT to ORD?

December is the weakest month at 68.9% on time, compared with 85.5% in February. Across the year that is 17 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.

Where to go next

Direction matters. PIT to ORD and ORD to PIT 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.

Key figures