Route reliability record
ORD→ATL
Chicago to Atlanta
- Flights
- 6,495
- Period
- September 2025 to August 2026
- Distance
- 606 mi
- Carriers
- 9
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 77.3%. The late ones land a little over an hour behind schedule. That rests on 6,495 ORD to ATL flights, of which Delta Air Lines flew 2,629 at 79.8% on time.
Best time to fly ORD to ATL: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 85.1% of the time and Tuesday flights 78.9%, against 74.1% for the route overall.
Delta Air Lines is the most reliable of the five carriers covered here at 79.8% on time across 2,629 flights.
Key figures
On time
74.1%
Arrivals under 15 minutes late, of 6,326 completed flights
Avg delay
81 min
Across delayed arrivals only, not all flights
Cancelled
2.31%
National rate is 1.89%
Best carrier
Delta
79.8% on time across 2,629 flights
These figures cover 6,495 flights between September 2025 and August 2026. Beyond the headline rate, 10.1% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
Which airline is most reliable on ORD to ATL
The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 79.8% of the time; American Airlines manages 59.5%. Sample sizes sit next to every figure, because a two-point gap across 754 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| PSA Airlinesthin sample | 1 | 100.0% | — | 0.00% | A+ |
| Spirit Airlinesthin sample | 16 | 87.5% | 127 min | 0.00% | A+ |
| Delta Air Lines | 2,629 | 79.8% | 84 min | 2.40% | B |
| Envoy Air | 365 | 77.6% | 62 min | 2.19% | B |
| United Airlines | 1,717 | 74.5% | 67 min | 1.34% | C |
| Republic Airwaysthin sample | 254 | 69.7% | 64 min | 4.33% | C− |
| Frontier Airlines | 719 | 67.5% | 97 min | 3.48% | C− |
| SkyWest Airlinesthin sample | 40 | 61.5% | 93 min | 2.50% | D |
| American Airlines | 754 | 59.5% | 94 min | 2.52% | D |
Frontier Airlines cancels 3.5% 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.
Flight by flight
Flights on ORD to ATL
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 Chicago to Atlanta
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. 2 of the top 5 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. MDW → ATLChicago to Atlanta | Delta Air Lines | 84.6% | 87.0% | 2.72% | 5am–8am, Wed | DL 1285 06:00 |
| 2. ORD → ATLChicago to Atlanta | Delta Air Lines | 77.9% | 79.8% | 2.40% | 5am–8am, Wed | DL 1264 05:30 |
| 3. ORD → ATLChicago to Atlanta | Envoy Air | 75.9% | 77.6% | 2.19% | 5am–8am, Mon | — |
| 4. MDW → ATLChicago to Atlanta | Southwest Airlines | 74.3% | 75.1% | 1.10% | 5am–8am, Tue | — |
| 5. ORD → ATLChicago to Atlanta | United Airlines | 73.5% | 74.5% | 1.34% | 5am–8am, Tue | UA 356 14:25 |
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 25 points, against 20 points between the best and worst carrier.
- 5am–8am1,514 flights85.1%
- 8am–11am1,293 flights81.7%
- 11am–2pm999 flights74.7%
- 2pm–5pm1,257 flights67.1%
- 5pm–8pm1,091 flights60.4%
- 8pm–5am341 flights63.0%
Scale runs 50% to 90%.
The 5pm–8pm window is where this operation falls apart: 60.4% on time, against 85.1% 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 5am–8am window is the busiest, with 1,514 flights scheduled in it.
Explore
Filter ORD to ATL 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 ORD to ATL, the best departure window is 5am–8am at 85.1% on time and the worst is 5pm–8pm at 60.4%, a wide gap of 24.7 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am85.1%
- 8–11am81.7%
- 11am–2pm74.7%
- 2–5pm67.1%
- 5–8pm60.4%
- 8pm–5am63.0%
best all US flightsScale 50% to 95%.
Across the year
When delays peak on this route
This route's year swings by 24 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 87.3% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. August was the busiest month here, with 626 flights.
Across the week, Tuesday is the strongest day at 78.9% on time and Sunday the weakest at 69.7%, a spread of 9 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 50% of the 133,000 delay minutes carriers reported here, and the remaining four split what is left.
- 50%Late-arriving aircraft
- 26%Carrier
- 20%National Airspace System
- 5%Extreme weather
50% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 133,000 reported delay minutes here, that single category outweighs weather by 11 to one. The split is drawn from 133,271 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 85.1% on time here.
Cancellations sit at 2.31% against a national 1.89%, which is ordinary. Diversions add another 0.29%.
Connections and stage length
What a delay here actually costs
10.1% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
The 606 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.
The return leg is a different operation and performs like one: it runs 69.0% on time across 6,493 flights, 5 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 5 points of difference.
The sample behind these figures is 6,495 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 ATL 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. September runs 87.3% on time and March 63.5%, a swing of 24 points. If the dates move at all, move them out of March before you think about anything else. 6,326 completed flights over 12 months sit behind that.
Common questions
ORD to ATL questions
How often is ORD to ATL delayed?
About one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 25.9% of the 6,495 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 ORD to ATL?
Delta Air Lines leads at 79.8% on time across 2,629 flights. American Airlines is at the other end on 59.5%, a gap of 20 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 ATL?
The 5am–8am departure window is the strongest at 85.1% on time. The 5pm–8pm window is the weakest at 60.4%, 25 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 ATL?
March is the weakest month at 63.5% on time, compared with 87.3% in September. Across the year that is 24 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
- ATL to ORD — the return legseparate record
- Chicago O'Hare International (ORD) delay statistics
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- Delta Air Lines on ORD to ATL79.8%
- Envoy Air on ORD to ATL77.6%
- United Airlines on ORD to ATL74.5%
- Republic Airways on ORD to ATL69.7%
- Frontier Airlines on ORD to ATL67.5%
- American Airlines on ORD to ATL59.5%
- ORD to LGA, a related route66.6%
- LGA to ATL, a related route75.5%
- ORD to BOS, a related route66.6%
- PSA Airlines on-time record100.0%
- Spirit Airlines on-time record87.5%
- Delta Air Lines on-time record79.8%
- Same route, different airline: where the carrier you pick matters most
- Why the first flight of the morning is statistically safest
Direction matters. ORD to ATL and ATL to ORD 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.