Route reliability record

ORD→RDU

Chicago to Raleigh

Flights: 3,592
Period: July 2025 to June 2026
Distance: 646 mi
Carriers: 7

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, 4 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 3,592 flights, of which Envoy Air flew 521 at 77.1% on time.

Envoy Air is the most reliable of the four carriers covered here at 77.1% on time across 521 flights.

On time

73.3%

Arrivals under 15 minutes late, of 3,514 completed flights

Avg delay

78 min

Across delayed arrivals only, not all flights

Cancelled

2.12%

National rate is 1.81%

Best carrier

Envoy

77.1% on time across 521 flights

These figures cover 3,592 flights between July 2025 and June 2026. Beyond the headline rate, 10.5% 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 RDU

The choice of carrier is not cosmetic here. Envoy Air arrives on time 77.1% of the time; American Airlines manages 61.8%. Sample sizes sit next to every figure, because a two-point gap across 555 flights means less than a ten-point one.

On-time performance by carrier on ORD to RDU
Airline	Flights	On time	Avg delay	Cancelled	Grade
SkyWest Airlinesthin sample	67	79.1%	65 min	0.00%	B+
Envoy Air	521	77.1%	54 min	1.73%	B
United Airlines	1,298	76.8%	77 min	1.00%	B
Republic Airways	1,018	73.5%	69 min	2.85%	C
Frontier Airlinesthin sample	131	66.4%	137 min	4.58%	C−
American Airlines	555	61.8%	96 min	3.42%	D−
PSA Airlinesthin sample	2	50.0%	85 min	0.00%	F+

American Airlines cancels 3.4% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.

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 28 points, against 15 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am418 flights85.3%
8am–11am836 flights81.9%
11am–2pm446 flights75.4%
2pm–5pm724 flights72.6%
5pm–8pm802 flights64.3%
8pm–5am366 flights57.3%

Scale runs 50% to 90%. Rows with fewer than 30 flights show a dash.

The 8pm–5am window is where this operation falls apart: 57.3% on time, against 85.3% 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 836 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.September best, July worst

July is the worst month at 64.8% on time, 17 points below September, the best at 81.6%. 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. May was the busiest month here, with 374 flights.

Across the week, Tuesday is the strongest day at 78.5% on time and Friday the weakest at 69.4%. 9 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 47% of the 74,000 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.

Late-arriving aircraft
47%
Carrier
28%
National Airspace System
17%
Extreme weather
8%
Security
0%

47% 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 74,000 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 73,584 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 85.3% on time here.

Cancellations sit at 2.12% against a national 1.81%, which is ordinary. Diversions add another 0.06%.

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. 10.5% 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.

The 646 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.

The return leg runs 74.4% on time across 3,589 flights, within about a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

The sample behind these figures is 3,592 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 81.6% on time and July 64.8%, a swing of 17 points. If the dates move at all, move them out of July before you think about anything else. 3,514 completed flights over 12 months sit behind that.

Common questions

ORD to RDU questions

How often is ORD to RDU 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 26.7% of the 3,592 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 RDU?

Envoy Air leads at 77.1% on time across 521 flights. American Airlines is at the other end on 61.8%, a gap of 15 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 RDU?

The 5am–8am departure window is the strongest at 85.3% on time. The 8pm–5am window is the weakest at 57.3%, 28 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 ORD to RDU?

July is the weakest month at 64.8% on time, compared with 81.6% in September. 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. ORD to RDU and RDU 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.

Key figures