Carrier performance at one airport
UA→ATL
United Airlines at Hartsfield-Jackson Atlanta International
- Departures
- 7,431
- Period
- June 2025 to May 2026
- Routes
- 6
- Rank here
- #1 of 12
United Airlines at Atlanta lands a B, 3 points better than the national rate of 77.4%. 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 7,431 flights, of which United Airlines flew 7,431 at 80.3% on time.
Measured against the airport rather than the country, United Airlines runs 3 points ahead of the 77.0% weighted average across all carriers at ATL. That is the comparison worth making: every operator here works the same runways, the same airspace and the same weather.
Key figures
On time
80.3%
7,299 completed departures
Avg delay
83 min
Across delayed flights only
Cancelled
1.44%
At ATL, this carrier only
Rank here
#1
Of 12 carriers clearing the floor at ATL
These figures cover 7,431 flights between June 2025 and May 2026. Beyond the headline rate, 8.4% 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.
Against the competition
Every carrier at ATL, ranked
The choice of carrier is not cosmetic here. United Airlines arrives on time 80.3% of the time; Frontier Airlines manages 63.2%. Sample sizes sit next to every figure, because a two-point gap across 19,091 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines (this page) | 7,431 | 80.3% | 83 min | 1.44% | B |
| PSA Airlines | 3,194 | 78.8% | 108 min | 4.82% | B− |
| Delta Air Lines | 241,168 | 78.4% | 60 min | 1.72% | B |
| Republic Airways | 2,717 | 77.0% | 77 min | 4.05% | B− |
| Southwest Airlines | 18,107 | 76.8% | 60 min | 1.17% | B |
| American Airlines | 6,851 | 75.9% | 107 min | 2.07% | B |
| Alaska Airlines | 1,463 | 75.4% | 57 min | 0.75% | B+ |
| SkyWest Airlines | 7,416 | 73.7% | 108 min | 2.17% | C |
| Envoy Air | 1,153 | 72.7% | 69 min | 3.12% | C− |
| Spirit Airlines | 6,049 | 70.5% | 75 min | 2.89% | C |
| JetBlue Airways | 2,469 | 70.5% | 92 min | 3.52% | C− |
| Frontier Airlines | 19,091 | 63.2% | 83 min | 2.33% | D |
PSA Airlines cancels 4.8% 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.
Route by route
Where United Airlines flies from ATL
United Airlines operates 6 routes out of ATL with enough volume to report. Route records inside one carrier at one airport still spread widely, because a short shuttle and a transcontinental have very different exposure to a late inbound.
| Route | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| ATL to EWR · Newark | 1,905 | 78.8% | 82 min | 3.04% | B− |
| ATL to ORD · Chicago | 1,575 | 75.7% | 91 min | 1.40% | B |
| ATL to IAH · Houston | 1,234 | 84.9% | 80 min | 1.22% | B |
| ATL to IAD · Washington | 1,085 | 80.1% | 86 min | 0.55% | B+ |
| ATL to DEN · Denver | 992 | 84.9% | 77 min | 0.40% | B+ |
| ATL to SFO · San Francisco | 640 | 79.7% | 63 min | 0.31% | B+ |
Departure window
Best time of day for this operation
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 21 points, against 17 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am1,270 flights89.0%
- 8am–11am1,562 flights85.7%
- 11am–2pm1,443 flights84.6%
- 2pm–5pm1,644 flights75.2%
- 5pm–8pm1,393 flights68.7%
- 8pm–5am119 flights68.4%
Scale runs 60% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 89.0% of the time, against 68.4% for the overnight 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.
Across the year
Seasonal pattern
July is the worst month at 72.5% on time, 15 points below February, the best at 87.8%. 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.
Delay causes
What holds this operation up
- 41%National Airspace System
- 32%Late-arriving aircraft
- 22%Carrier
- 4%Extreme weather
- 0%Security
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 49,000 minutes out of 119,000, against a national NAS share of 21%.
Cancellations sit at 1.44% against a national 1.80%, which is ordinary. Diversions add another 0.34%.
8.4% of arrivals land an hour or more late, close to the national 8.2%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route are the an hour and a half kind, which a normal layover absorbs.
The sample behind these figures is 7,431 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.
Put together: the calendar is the biggest lever here, not the carrier or the hour. February runs 87.8% on time and July 72.5%, a swing of 15 points. If the dates move at all, move them out of July before you think about anything else.
Common questions
United Airlines at ATL
How often is United Airlines at ATL 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 19.7% of the 7,431 flights in this analysis, against 22.6% nationally. Delayed flights are late by an hour and a half on average.
Which airline is most reliable on United Airlines at ATL?
United Airlines leads at 80.3% on time across 7,431 flights. Frontier Airlines is at the other end on 63.2%, a gap of 17 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 United Airlines at ATL?
The 5am–8am departure window is the strongest at 89.0% on time. The 8pm–5am window is the weakest at 68.4%, 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 July delays on United Airlines at ATL?
July is the weakest month at 72.5% on time, compared with 87.8% in February. Across the year that is 15 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
- United Airlines network-wide record
- Hartsfield-Jackson Atlanta International (ATL) all carriers
- ATL to EWR route record78.8%
- ATL to ORD route record75.7%
- ATL to IAH route record84.9%
- The best time of day to fly, according to 7.05 million flight records
- Connecting flights: how much buffer the data says you need
Source: US DOT Bureau of Transportation Statistics, on-time performance data, June 2025 to May 2026. Updated monthly. How this data is collected.